Title: Urban morphological theory and spatial differentiation in a Caribbean city
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00099367/00001
 Material Information
Title: Urban morphological theory and spatial differentiation in a Caribbean city residential land use from 1948 to 1975 in Santo Domingo, the Dominican Republic
Physical Description: vii, 178 leaves : ill., maps ; 28 cm.
Language: English
Creator: Tupper, Howard M., 1941- ( Dissertant )
Antonini, Gustavo A. ( Thesis advisor )
Marcus, Robert B. ( Reviewer )
Starnes, Earl M. ( Reviewer )
Ewel, katherine, C. ( Reviewer )
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1982
Copyright Date: 1982
Subject: Land use, Urban -- Dominican Republic -- Santo Domingo   ( lcsh )
Geography thesis Ph. D   ( lcsh )
Dissertations, Academic -- Geography -- UF   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
Thesis: Thesis (Ph. D.)--University of Florida, 1982.
Bibliography: Bibliography: leaves 165-177.
General Note: Typescript.
General Note: Vita.
Statement of Responsibility: by Howard McKay Tupper.
 Record Information
Bibliographic ID: UF00099367
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000319156
oclc - 09320411
notis - ABU6007


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I have had innumerable occasions over the past years to be grate-

ful to many persons whose encouragement, patience, confidence, and

expert assistance have made this research possible. My decision to

become a geographer was invited and supported by Dr. Clark Cross. The

intensely rewarding classroom experiences created by Dr. James R.

Anderson and his dedication to the geography profession have been in-

spiring. There have been other educators with whom I have had the

pleasure of studying. Dr. John Saunders taught me demographic prin-

ciples; Mr. Carl Feiss guided the preparation in urban studies.

I greatly appreciate their dedication to their profession.

Others whose academic excellence I admire have also been my

friends, helping me to overcome obstacles to and enjoy the rewards of

academic life. Probably none has been more patient and helpful and con-

cerned for my welfare than Dr. Gustavo A. Antonini. May the wind never

fail, and the sea remain gentle. Dr. Katherine Carter Ewel has been a

sympathetic friend whose intellect and insight are well known to her

friends and associates. And, I am thankful for the gracious goodwill

of Drs. Robert Marcus and Earl Starnes.

It is appropriate to mention two university programs that have

contributed so much to my education. The Center for Latin American

Studies' demography program generously supported both my training as a

population geographer and my residency in the Dominican Republic. The

Department of Geography teaching assistantship provided invaluable class-

room experience for which I am deeply grateful. The interaction shared

with the department faculty, staff, and students has given me many

pleasant memories.

There are those individuals whose skills become invaluable in the

preparation of such a study. Mr. Jos3 J. Hungrfa was a wonderful

Dominican host who extended a generous welcome that included the re-

sources of the Geographic Institute. I extend my sincere appreciation

to Sue Kirkpatrick for her typing and editorial skills so important to

the preparation of this dissertation.

To John, Christine, and Earnest who have wanted only the best for

me, I thank you and am happy that you share the pleasure that comes with

the'attainment of this goal in our lives and the expectations of the





ABSTRACT . . . ... . . vi


ONE INTRODUCTION .. . . . .. 1

Purpose of Study .
Research Objectives .
The Study Plan .


The Dominican Republic .. ........
Santo Domingo City . . . .
Recent Urbanization . . .
The Housing Problem .......


Concentric Zone Model
The Applicability of the
Caribbean . .
Sector Model . .
The Applicability of the
Multiple Nuclei Model .
The Applicability of the
Caribbean . .

Concentric Zone

Sector Model to

Multiple Nuclei

Model to the

the Caribbean

Model to the


Aerial Photography Data Base .. .... .. .. .
Temporal and Spatial Framework . .
Mapping Criteria ....
Aerial Photography Interpretation .. ......
Field Survey ...........
Residential Land Use Definition of the Field Sample .

. . . .
. . . . .



Allocating Zone and Sector Location . ... 84
Testing the Models of Land Use Change ...... 90
Testing the Models for 1948 Residential Land Use 97
Factor Analysis . . . ... .104

SIX LAND USE CHANGE . . . .... 115

1948 Land Use ... . . . 115
1974 Land Use ................... 123
Land Use Change, 1948-1974 . . .. 127

LATION . . . ... 140

Evolutionary Theory of Urban Change . ... 140
Housing Conditions . . . . 143
Population Estimates . . . 145
Housing Typology . . . . 149


REFERENCES . . . . ... .. ..... 165


Abstract of Dissertation Presented to the Graduate Council
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy



Howard McKay Tupper

August 1982

Chairman: Gustavo A. Antonini
Major Department: Geography

Land use change, specifically the spatial patterning of residen-

tial land use change, in the capital city of the Dominican Republic was

examined over a 27-year period when both the nation and city underwent

many important changes, including urbanization. The principal objective

of this study is to assess the usefulness of urban morphological theory

to explain the growth of Santo Domingo. Associated objectives include

the identification of trends in the urban change and alternatives for

development over the remaining decades of the century.

The research methodology employed three data bases. Both 1948

and 1974 aerial photographic coverage of the city provided information

for a five-category land use classification system, and the results of

the interpretation were mapped in units of one hectare. Final maps are

scaled at 1:80,000. The third data base was a 10-percent sample of all

streets in which land uses were determined in a block-by-block canvass

that included sampling for 40 variables measuring lot and structure


The data bases were merged by the location of each hectare of

urban land included in the city. Zone and sector models were tested to

assess whether they were useful in explaining the spatial differentia-

tion over the study period. The 45 variables describing urban land

use in both 1948 and 1975 were factor analyzed to discriminate among

low-, medium-, and high-income residential land uses.

The city, entering the early stage of industrialization accom-

panied by extensive urbanization, exhibits a sectoral pattern of land

use change. The single example of a zone was found for high-income

residential land that had aggregated at what had been the urban fringe

about 1948, before the inception of the present phase of modernization.

A general absence of filtering, little suburbanization, and extensive

marginal housing at the city's edge are evidence that this Caribbean

capital departs from the morphological patterns identified for Anglo-

American cities of comparable size and importance.


Purpose of Study

Contemporary urban theory explaining the area differentiation of

the city can be organized according to social systems, group decisions,

and habitat. First, there is the theory which relates to the system of

social organization at the local community level and involves the

social structure and associated institutions that constitute the urban

environment. Second, there is the theory of behavior of city dwellers

expressed in attitudes and ideas and manifested in decisions affecting

urban development. Third, there is the urban habitat.in its more inclu-

sive sense of people, technology, resources, and interrelationships.

The latter is the concern of human ecologists and urban geographers.

These geographers as well as urban ecologists are specialists in the

physical expressions of social systems, group decisions, and habitat

that are termed urban morphology. This study is concerned with the for-

mal, or structural, city that is included in residential land use and

which is assumed to be representative of the ecological relationships

among urban systems.

Accumulating urban morphological theory is based upon wide-

ranging conditions encompassing urban experiences in different cultures.

However, a majority of published research reflects a Western, developed

society orientation, and there is the possibility that the theoretical

constructs may not apply to developing economies which are not yet as

fully modernized nor capitalistic.

Research into the urban milieu of other regions could be useful

for testing the validity and reliability of urban theory drawn from

Anglo-American and Western European cities. Urban morphological study

of Caribbean cities, modest by comparison with that accomplished else-

where in the Western Hemisphere, is insufficient to conclude that the

hypotheses advanced for urban change are applicable to such rapidly

modernizing cities as Kingston, Havana, or Santo Domingo.

If modernization in these Caribbean cities departs from the pro-

cess identified in the United States, then these capitals may evolve

spatial configurations distinct from Anglo-American cities. The impli-

cations for urban growth planning are important, especially for those

officials who are concerned with efficient utilization of scarce re-

sources. Research of Caribbean urban geography has the potential of

contributing additional, valuable information expanding our knowledge of

the processes of urban change. Dwyer (1975, 248) has said,

What is needed is more extensive investigation into the Third
World city in such disciplines as geography, sociology, social
anthropology and psychology in order to evaluate further the
economic, social, cultural and other forces at work in shaping
patterns of urban development. Existing knowledge of the
urbanization process in the nature of housing problems in
particular is all too often either ignored or badly applied.

Santo Domingo, capital city of the Dominican Republic, is a

rapidly urbanizing city that is undergoing modernization. Because of

its importance both as a regional and national center, Santo Domingo

has required a proportionally larger share of the nation's resources

than other Dominican cities. Because of its more rapid population

growth, the capital will require an even larger share in the immediate


This study is directed specifically at identifying base-line

conditions in Santo Domingo of land use and housing which must be evalu-

ated in formulating a comprehensive housing program. "Housing clearly

reflects the economic and demographic structure of a society-its level

of development, the distribution of its income, the rate of population

growth, and the pace of expansion" (Gilbert and Ward 1978, 285). This

study of residential land use change will identify conditions in intra-

urban form under the tacit assumption that housing is indicative of

socioeconomic classes and that there is a reasonably clear relationship

between social structure and housing.

There is a need for systematic investigation of housing grouped

to explain urban structure and social area differentiation (Herbert 1973,

124-127). Recent quantitative studies generally have ignored residen-

tial structure and land use in modernizing societies.

This study of Santo Domingo is an effort to uncover cross-

cultural urban ecological conditions explained by general theory of

urban change including three models of land use change. These models

include concentric zones, sectors, and multiple nuclei. Santo

Domingo was selected as representative of the urban environment in a

Caribbean setting. It is undergoing modernization in a region experi-

encing much change that may be best understood within the context of

urban theory.

The complexity of urban conditions restricts the scope of any

analysis of the mechanisms and the social organization which accompany

change. But land use study is a necessary step in developing a compre-

hensive understanding of conditions in the city. Residential land use,

specifically housing in its physical and social connotations, repre-

sents the largest area of the city, the majority of all structures, and

the greatest portion of the metropolitan population, and involves a

great many of the daily activities of city dwellers.

This research is focused on land use change in Santo Domingo over

the 1948-1975 period. Included in the land uses were three residential

categories representative of socioeconomic status; another category of

other land use that was an aggregation of public, commercial, and in-

dustrial uses; and a fifth use of open, undeveloped land. The research

involved the analysis of several data bases in order to address a num-

ber of timely, important questions.

Research Objectives

There were four major goals of the study. Each included a number

of specific questions relating to land use and housing within the con-

text of urban ecological conditions. These four objectives are

1. To determine the extent of modernization Santo Domingo sus-

tained over more than one-quarter century. Specific objectives included

(a) determining whether modernization had transformed the traditional

morphology of the city; (c) determining whether land uses were becom-

ing more homogeneous; (d) determining whether growth of residential land

use was concentrating, and, if so, whether this occurred along the

transportation corridors; (e) determining whether there was evidence

that density of land use was increasing and that a gradient of land use

existed; (f) determining whether there was an evolutionary sequence to

growth which included evidence of decentralization.

2. To determine which of the ecological models of urban change

was (were) best in explaining land use patterns. Specific objectives

included (a) determining the direction of change; (b) determining

whether there was evidence of a housing cycle that incorporated filter-

ing, the shift in the use of housing from higher to lower socioeconomic

levels of the occupants.

3. To identify housing according to socioeconomic level. Spe-

cific objectives included (a) determining whether the field survey of

housing could predict land use as identified from aerial photography;

(b) ascertaining whether housing aggregated by ecological divisions in

land use change models.

4. To isolate those aspects of the urban condition in Santo

Domingo which would assist in planning for the future of the city.

Specific objectives included (a) determining the likely trends in the

immediate growth of the city; (b) identifying desirable alternatives

to expected urban change; (c) recommending possible means for achiev-

ing desired alternatives to growth patterns identified for the city's

continued expansion.

The Study Plan

There were three data bases incorporated into the study of land

use and housing in Santo Domingo. Aerial photographic coverage, accumu-

lating since 1916, was examined at the Geographic Institute of the

Autonomous Univeristy of Santo Domingo, and two flights were selected

which were representative of the city's condition, one prior to the

latest transformation from a traditional to modern capital. The 1974

coverage was the most recent available and provided up-to-date informa-

tion about the extent of modernization.

The photographs were interpreted during 1979-1980 at the Carto-

graphic Laboratory of the University of Florida's Center for Latin

American Studies. The 1974 photography was interpreted first, and land

use was grouped into three residential categories according to socio-

economic indicators of low-, medium-,and high-income housing. The land

use information was transferred to a land use map scaled at 1:12,500.

A grid of one-hectare cells was overlaid on the land use map in order

to aggregate the predominant use into hectare-sized blocks that would be

comparable with the 1948 conditions as well as the field survey results.

Thus, the largest proportion of any land use determined the classifica-

tion for the hectare cell. The coordinates of longitude and latitude

for each cell were used to store the land use information for the later

analysis that was to include both comparison with 1948 aerial photog-

raphy and the 1975 field sample of city streets.

The photography for 1948 was interpreted in like manner. A land

use map, scaled at 1:12,500 was produced, and the information, aggre-

gated into hectare-sized cells, was stored according to the geographic

location in the same grid system as used for the 1974 base year.

In 1975, a survey of approximately 10 percent of the nearly

1,400 streets was conducted in order to collect information about hous-

ing in Santo Domingo. The entire length of each randomly selected

street was traversed. Field information concerning 40 variables relat-

ing to socioeconomic level of residents, the building materials used

in construction, general state of repair of structures, number of

floors, and extent of infrastructural services was collected, as well

as data about other land uses and nonresidential structures also found

along the street. Over 9,100 structures were included in the sample.

They were located as sites on a map of the city which included the

same hectare-sized system of cells used for location of the remotely

sensed data. One-half of the sites found in each sample hectare were

randomly selected and stored for analysis.

From the aerial photographs, five land use maps for each of the

two years were completed which displayed the individual land use cate-

gories and which became the bases for comparative analysis. The merge

of the computer-stored data produced land use change information aggre-

gated by hectare cells which were mapped to display the 1974 land uses

of all 1948 hectares which had changed use during the intervening years.

In order to test the applicability of the zone and sector models

as explanations of the land use change patterns, the models' geometric

configurations were superimposed upon the 1974 and 1948 land use maps.

Each hectare cell of land was given a value for its location in both

a zone and sector. Variations from the expected frequencies of land

use in each zone and sector were tested for significant differences.

The field survey of structures included 747 hectares of the city's

area in 1974-1975. Only 44 percent of the survey area was found to be

exclusively residential. Of 520 hectares found to contain some propor-

tion of residential structures in both the survey and 1974 aerial

photography, 333 were entirely developed in housing. It was nec-

essary to arrive at some criterion for designating the remaining hec-

tares as either residential or nonresidential in order to relate the

housing information to land use and land use change over the 27-year

period. All proportions of residential to nonresidential structures

per hectare were considered in relation to the loss of information

that would occur under various land use mixes. The 50-percent cri-

terion was chosen after careful analysis.

Once the minimum proportion of residential structures allowable

in any hectare cell designated residential was arrived at, the survey

data were merged with the remotely sensed data bases by cells of resi-

dential land use in order to estimate housing conditions throughout

the city during the 1974-1975 period. The field variables relating to

housing and neighborhood conditions were augmented with others which

included the land use change model configurations and the distance of

each hectare to the city center. To reduce the housing information to

.a few indicators of socioeconomic levels of residential land use, the

data were factor analyzed. Four factors were produced, three of which

discriminated among the field variables relating to socioeconomic



The Dominican Republic

The Dominican Republic is the larger of the two nations sharing

the island of Hispaiola in the Caribbean archipelago. Its long Spanish

heritage began with the founding of the first permanent European settle-

ment in the New World at what is now the capital city of Santo Domingo.

Culture and language continue to bind Dominicans to their Latin American

cousins and the Spanish mother country. But four hundred years of in-

sularity, demographic and economic stagnation resulting from Spanish

colonial indifference, and numerous foreign incursions have contributed

to the evolution of a provincial, traditional island society which

shares a Caribbean culture based on similar history, ethnicity, politics,

and economy. Ruled by a small elite of ranching families who were

neither wealthy nor a landed aristocracy so typical in Latin America,

the republic was two centuries later than the rest of the Spanish-

speaking New World in experiencing the concentration of riches and

power in a Dominican aristocracy (Bell 1981, 111-116).

The Dominican oligarchy is comprised of a few families of colonial

Spanish heritage and a small number of wealthy Dominican families who

became successful under the long Trujillo era from 1930 to 1961 and

managed to retain their influence and continue to share power. In

1960, Bosch (1978, 266) described this class as including politicians,

bankers, industrialists, wholesalers, doctors, lawyers, merchants, land-

owners, military officers, prelates, and intellectuals.

The Dominican Republic can be described as a social democracy com-

mitted to private ownership of property and free enterprise. Although

the government has been antisocialistic, the extensive holdings of the

Trujillo family that were expropriated after the dictator's assassina-

tion in 1961 remain to a large extent in the public sector.

The island nation's economy is primarily agricultural. A warm,

moist climate influenced by the Trade Winds coupled with a relatively

large expanse of arable land, especially the rich Cibao Valley of the

Yaque del Norte River, have sustained the traditional cash cropping of

sugarcane, coffee,and tobacco, while substantial harvests of food crops

including rice, beans, peas, and fruits are grown on the many small

holdings found throughout the nation. Even the industrialization is

tied to the agricultural base, for sugar growing and processing employ

about 54 percent of all industrial labor (Repdblica Dominicana 1977, 4).

Relatively rich in natural resources in comparison with the other

Caribbean nations, the Dominican Republic has a large labor supply as

well, but does not enjoy sufficient capital to pursue a massive national

development program simultaneously incorporating improvements in all

sectors of the economy. Between 1966 and 1972, total national expendi-

tures averaged RD$ 249.01 million with social and economic portions

about equal in the national budget (Table 2-1).

General economic conditions include the need to increase agricul-

tural production and the food-processing industries that help feed a

rapidly increasing population. But such economic expansion is impeded

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by the loss of capital from the profits expatriated by extranational

corporations. There is the loss of valuable foreign exchange expended

to purchase foodstuffs that might have been grown at home had more land

and capital been invested in food staples rather than cash crops. The

high prices that are charged for the fuel that the republic must import

deprive the economy of badly needed revenue.

Probably about one-half of all Dominicans now reside in cities.

Although the provincial capitals draw many rural poor, still the largest

numbers of migrants are found in Santiago and Santo Domingo (Figure 2-1).

It can be estimated that 20 percent of all Dominicans live in the capi-


Santo Domingo City

Founded about 1502 along the Caribbean coast at the mouth of the

Ozama River, Santo Domingo was established as the colonial communication

link and base for Spain to explore the New World. The island is in the

hurricane track; the town was moved from its original site on the east

bank of the river to the present position after a hurricane destroyed it

shortly after its founding. Even as recent as 1930, Santo Domingo was

destroyed by another tropical storm.

The entire city (Figure 2-2) is in relatively homogeneous terrain.

The immediate geologic structure is porous, well-drained, soft calcareous

and very hard, coraliferous limestone rocks arranged in relatively flat

terraces which parallel the sharply sculpted coastline. Kilometer-wide,

nearly level ledges rise to about 70 meters elevation in the west, about

40 meters in the east.

































The Ozama River joins with the Isabela River at the northeast

limit of the city. These rivers drain a broad watershed which incor-

porates an agricultural interior largely cultivated in sugarcane. They

have cut deep channels in the hard limestone substrata. Three bridges

in the city crossed these in 1975, one spanning the Isabela River, and

the other two connecting the eastern part of the city to the main com-

mercial, industrial, recreational, cultural, and residential city.

There are a few narrow marshlands along the floodplain which disappears

in places along the Ozama as it flows through the city to the Caribbean.

The western part of Santo Domingo is built upon a flat peninsula

between these two rivers and the Haina River. In the northwest, the

land is dissected by steeply sloping stream beds that have created a

relatively hilly terrain. Until recently, land here had been sparsely

settled. High ground has made the cost of providing water mains and

sewers prohibitively expensive,and local water shortages impede develop-


To the east across the Ozama, the land tends to be flat with

shallow, poor soil and extensive rocky outcroppings that contribute to

an arid, desolate landscape of small trees, shrubs, and grasses.

Actually, most land within the present confines of the city is of poor

quality except for a few areas in both the northeast and northwest

where rural settlements used to exist.

The city's presently developed area is extensive in comparison

with its size prior to World War II. The historic center, as shown in

Figure 2-3, with its colonial structures several floors high and ruined

fortifications, comprises an area of slightly more than one square

kilometer. Included in this nearly five-hundred-year-old city are the

restored castle of Diego Colon, the oldest cathedral and hospital, the

Plaza Coldn, city hall, main post office, and other important struc-

tures. According to the first national census in 1908, the colonial

center contained 45 streets and had 2,862 houses. The focus of the city

was the Plaza Col6n which is linked to the ruin of the city wall at the

main gate, Puenta del Conde, by an avenue of the same name. Unlike

many colonial cities elsewhere that were defensive in function, Santo

Domingo still has some of its original fortifications. Since the wall

foundations remain in place, circumferential streets with radial connec-

tions to the main plaza are not in evidence around the city center. On

the east, the fortifications terminate at the steep bank of the Ozama

where the port wharves have been built. Across the river on hills to

the northeast was the small village of Pajarito and a few homes scat-

tered along the bank (Hazard 1873, 219-223).

President Trujillo took office the same year a hurricane in 1930

demolished the capital and claimed thousands of lives. There were

10,000 families without homes. During the next five years, the govern-

ment and private enterprise rebuilt over 6,000 homes, but one-third of

the storm's victims were without permanent housing (Bonnelly 1960, 40).

By 1950, an additional 23,000 housing units had been constructed, bring-

ing the total stock of housing to 41,161. The deficit in housing was

estimated to be about 1,000 units (Republica Dominicana 1960, 40).

Other major developments in the city included the port develop-

ment project begun in 1935. The Ozama entrance was deepened, a break-

water was constructed at the western side of the river mouth to protect

the inner harbor, and over one and one-half kilometers of wharves and

56,000 square meters of warehouse space needed.

By the beginning of World War II, the city had increased in area

contiguous to the west and north of the colonial center. To commemorate

his silver jubilee in 1955, Trujillo authorized construction of the

international fair project which was built at what was then the western

edge of the city. La Feria cost over RD$ 30 million, a huge sum at a

time when the national budget was about RD$ 120 million, but the

Dominican economy was flourishing. To accommodate the anticipated

thousands of visitors to the exhibition, the government, with U.S. in-

vestment, constructed a major tourist hotel, El Embajador.

The Dominican Republic was relatively late entering the Caribbean

tourism industry. The Jaraqua Hotel had been the first large tourist

hotel, but the stigma of the dictatorship discouraged tourism, and only

three large hotels had been built in the city by 1965, none of which

was kept in good repair (Bell 1981, 339-341).

After order was restored following the civil war in 1965, the

nation has enjoyed nearly two decades of reasonably peaceful, osten-

sibly democratic government. An ambitious project to restore the

colonial center is nearly completed and is encouraging a growing tourist

industry. Many of the centuries-old structures have been returned to

their former magnificence when Santo Domingo was the capital of the New


The city port is now used almost entirely for welcoming the thou-

sands of tourists who arrive by cruise ship. Since 1968 when tourists

numbered 68,500, the flow of visitors has reached half a million,

10 percent of whom travel to the island aboard these ships (Repdblica

Dominicana 1978). Most commercial shipping now unloads and loads at

the port of Haina at the western fringe of the capital. In 1978, the

government authorized the expenditure of RD$ 4.7 million to develop

Haina as the main commercial port.

Recent Urbanization

The old city remains the hub of commercial and social activity.

Many large shops, offices, churches, and businesses share the crowded

space, and the lack of high-rise structures, the narrow streets and traf-

fic congestion, and the noise and dust are inducing some activities to

relocate. With a population that is doubling each decade, this city

that was built to serve 30,000 must now provide for nearly one million


Business, commercial warehousing, and light manufacturing can be

found in newly constructed structures along many avenues, especially

Avenida J. F. Kennedy, the northern extension of Avenida M6ximo G6mez,

along Autopista Duarte and Carretera Sanchez, and in the industrial com-

plex of Herrera. There are over 600 firms scattered over the city, e.g.

Metadom, a scrap metal processing plant established by a Spanish firm at

what was once the edge of the city but which has been surrounded by

residences. There are other industrial concentrations in the neighbor-

hoods of La Fe and Luper6n, and across the Ozama along Carretera Mendoza

in Los Minas (Berg6s 1973, 3-4).

The city's growth has been largely unregulated. Although builders

are encouraged to observe such official regulations as published in the

New York City housing code, the absence of zoning restrictions and a

comprehensive plan for urban development have left the expansion of

Santo Domingo to the designs and whims of the construction industry and

a host of official agencies which have little power to enforce compli-

ance with building codes. It is commonplace to find residences, stores,

professional offices, and even light manufacturing scattered along a

street. A new apartment house of six floors can be built next door to a

middle-income, ranch-style home.

Strip commercial activities can be found throughout the city.

The more notable stretches include the extensive development along

Avenida Duarte, beginning at the downtown market area and extending

along most of its length. Similar strip development is found along

Avenues San Martin, 30 de Marzo, Mdximo G6mex, Sabana Larga, Maria Mon-

tez, and Padre Castellanos.

In the most recently constructed residential areas, commercialism

has been centralized to a large extent. The shopping centers, super-

markets, and public markets accommodate neighborhood shoppers. An

example is the Naco shopping center which services a middle- and high-

income residential community built on land that had been the only inter-

national airport for the nation (Figure 2-4). In 1955, the airport was

moved to Punta Caucedo, 29 kilometers to the east of Santo Domingo.

Aeropuerto de las Amdricas was completed in 1971.

Other widely dispersed commercial enterprises include food stores,

called colmados. They are often managed by their owners and resemble

the Ma-and-Pa corner grocery store in large U.S. cities (Norvell 1969,

105, 108-109). Other domestic shopping can be done at the few central

public markets.
















Produce is trucked into the city primarily to the wholesale dis-

trict adjacent to the public markets, and the storage wholesalers dis-

tribute to the markets and the colmados.

Public and institutional buildings, especially schools and ec-

clesiastical structures, also are dispersed widely. There are concen-

trations in the colonial city where restored buildings are providing the

government with much badly needed space. There are other public com-

plexes at La Feria and at the Huacal (a major government office build-

ing), at the sports stadium, around the national palace and along

Avenida P. Henriquez Urbana, at the Museum of Man and symphony hall

facilities, the universities, and at the intersection of Avenida Luper6n

and Avenida 27 de Febrero.

From 1970 to 1977, the Dominican government spent an average of

RD$ 28 million on roads and bridges, with most construction on projects

in or near the capital. These included a four-lane, divided highway

extension to San Crist6bal, another along the northern part of the city

to connect this by-pass with a fourth bridge crossing the Ozama River,

and the Avenida de las Americas which now extends beyond the airport

to San Pedro de Macoris. The Sanchez bridge has helped to ease traf-

fic congestion at the Ozama River.

Automobile traffic has become a major problem. In 1948, there

were fewer than 1,400 registered automobiles and by 1961, they had

increased to only 6,000 private cars in the entire nation; however,

10 years later, there were over 26,000. In 1975, there were about

49,000 registered automobiles, most operated in the capital city

(Rep6blica Dominicana 1952; Bell 1981, 140).

Several reasons account for this rapid expansion in private auto

ownership. In 1962, President Balaguer decreed the end to the

Trujillo-owned taxi monopoly and conferred ownership of 5,000 city taxis

on their drivers. The operators have had a powerful union which sup-

ported the president during his long administration, and, in exchange,

they received a gasoline subsidy that kept the price of fuel low. Addi-

tionally, most intracity public transportation was relegated to the

taxis called pdblicos which numbered 25,000 in 1977 and provided an in-

formal public service on a fee-for-hire basis along routes selected by

their drivers. Bus registration increased from 316 in 1961 to about

1,860 in 1975, with most of the buses being used in intercity transporta-

tion. The municipal bus service has increased dramatically since

President Guzman expropriated all public transport in 1981, including

the pdblicos which are now rented at reasonable rates to their operators.

The Dominican Republic has a better articulated system of cities

than have Cuba and the non-Spanish-speaking Caribbean nations (Clarke

1974, 225). Yet, much industrial growth between 1968 and 1977 occurred

in either Santo Domingo or Santiago. The industrial Incentive Law was

enacted to encourage "the most rapid and effective industrial promo-

tion of the country's economy with the purpose of obtaining permanent

sources of employment and income for our population and a diversifica-

tion of our national economic base" (Presidential Decree of April 23,

1968). The law allows new industries to be exonerated from 90 percent

of import duties and taxes on raw materials, containers, packing mate-

rials, fuel and lubricants, and 50 percent of net income when re-

invested in the industry. In order to discourage the concentration of

investment in areas already industrialized, the government planners pro-

posed that Santo Domingo- and Santiago-based firms be allowed an 8- and

12-year exemption, respectively, while elsewhere exonerations were

extended to 15 to 20 years. Although the plan was to encourage indus-

trial dispersal, create new jobs in smaller cities, and, thus, slow

urbanization in the metropolitan areas, nevertheless, many of the new

industries established under the law were capital intensive. Only 9,400

new jobs were created in a decade when population increased by more than

one million (Bell 1981, 349-351).

There are 10-20 rural laborers underemployed or out of work for

each small farm. The goal of the agrarian reform program begun in 1962

was to improve rural living conditions sufficiently to stem the flow of

farmers whose numbers threatened to inundate the provincial and regional

capitals. From 1960 to 1970, the national population increased from 30

to 40 percent, and Santo Domingo almost doubled in size (RepUblica

Dominicana 1971b, 26). An annual urban growth rate of 5.9 in the capi-

tal was well above the annual national rate of 3.6 (Davis 1972), an

indication of the magnitude of rural-to-urban migration.

By 1975, another 200,000 migrants are believed to have moved into

Santo Domingo. Most are believed to have been without jobs and poor.

They probably became new residents of such marginal settlements as

those that have clung to the steep banks of the Ozama River where at

least 200,000 may have sought shelter (Fanger 1978, 26).

The Housing Problem

Residential land use is a reflection of demographic conditions

and, although not directly tied to economic conditions, is nonetheless

often the largest portion of urban investment (World Bank 1978, 285).

The traditional values manifested in urban institutions as well as the

particular social and economic conditions of city life have caused

rapid in-migration to cities. Where urbanization has outpaced the

expansion of the housing sector, severe housing shortages have occurred.

In the Caribbean, the rate of absorption of land into urban use

has increased less rapidly than the rate of population growth. The

requirement for space is a function of the total urban population and

the density or intensity of use for diverse urban activities. Land

development often includes the loss of open space, some of which is

vital for groundwater recharge, recreation, future urban growth needs,

the control of pollution, etc. The horizontal sprawl of cities in-

creases transport costs, the need for streets, water, sewer, electric-

ity, telephone and other utility extensions, provision of more clinics

and hospitals, more schools, more fire stations and police barracks,

more branch stores, supermarkets, etc. This expansion requires both

land and capital whichmay be severely limited. Improving municipal ser-

vices often can be accomplished more cheaply and consume less land by

intensification than by extension (Lamm 1973). By connecting addi-

tional utility customers on existing systems, adding more floors to

hospitals, schools, and police stations, it is possible to conserve

land, while savings in costs can be used to improve housing for the

city's inhabitants.

Since the growth of population and structures will lead to changes

in a city's structure, residential land use has been of principal con-

cern to those investigating or seeking control of urban land use

(Bourne 1981, 19). There is the advantage to property owners, mortgage

investors, realtors, and others of knowing the probable or alternative

patterns of city growth.

Unlike the Anglo-American experience where climate and absence of

adequate housing have acted as a constraint on urbanization (Forrester

and Mass 1975, 25-26), conditions in Dominican cities have not impeded

in-migration (Makowski 1975, 55-56; Aversch and Levine 1971, 157).

Widespread, endemic poverty coupled with a moderate, subtropical cli-

ate allowsyear-round occupancy of rudimentary shelter, fostering exten-

sive marginal housing.1

Forrester (1974, 22-24) suggests that housing supply may be re-

lated to stages of urban growth, exerting an independent effect on inter-

urban migration as the city progresses through the industrialization

phases of modernization. If this is the case in Santo Domingo, then

Dominican urban problems may be similar to those experienced in Anglo-

American cities at the turn of this century (Herbert 1973, 36-45). But

unlike the latter places, the island capital has far less capital and

access to resources to engage in the similar solutions to housing de-


There is an important difference between the U.S. urban situation

in housing and that found in Santo Domingo. In the former cities, there

is an excess of deteriorated, even abandoned buildings, while in Santo

Alonso (1971, 4) prefers the term marginal. See John Collins
(1973, 118) for a discussion of other terms: squatter emphasizes
legalities in obtaining shelter; shantytown implies certain physical
conditions; uncontrolled urban growth is preferred by Collins because it
implies the interdependence of physical, social, and economic factors.
The latter choice also implies planning which is generally lacking in
the Caribbean.

Domingo, there is simply no housing available for the majority of those

requiring it, at any price, and certainly not within the means of most

urban poor. The spread of cardboard and palm-thatched huts is the mar-

ginal dweller's response to unsuccessful housing searches. As long as

vacant urban land exists to accommodate these poor people, it is likely

that the inflow of more people can be expected to continue. Assuming

that the Dominican population was over five million and that the average

family size was five persons in 1974, the Secretary of State for Health

and Public Welfare estimated the national shortage as nearly 400,000

units, of which 30-50 percent was located in Santo Domingo (RepOblica

Dominicana 1974; Fanger 1978, 26; Sanchez Cdrdova 1975, 42).

Five agencies participate in the Dominican housing program: the

National Housing Bank, the Technical Office of the President, the

National Institute of Housing, the Institute of Public Housing, and the

Savings and Loan Bank. Combined annual production of housing has

averaged 3,000 units, 1,000 of which were built in the capital. There

is a yearly increment in the demand for housing of about 10,000 units.

In the 1975-1985 decade, it has been projected that 115,000 more hous-

ing units will be required to prevent a further increase in the present

shortage. At a conservatively estimated cost of RD$ 4,000 per unit,

the annual cost would amount to RD$ 45 million, well above the expendi-

ture now being made for housing (Table 2-1).

There are approximately 200,000 households in Santo Domingo, and

only about 42 percent of them are able to obtain housing within the

commercial market. Less than half of all families needing housing were

able to quality for the minimum standard provided by those agencies

actively participating in the housing construction industry (Fanger

1978; Alonso 1971, 7; Sanchez C6rdova 1975, 42). The rest, numbering

over 100,000 families, have had to house themselves, often in marginal

settlements comprised of structures costing one-third of what is con-

sidered the minimum standard home. It is reasonable to assume that 70

percent of all housing each year has been improvised from discarded or

nearly worthless materials; only about 10 percent of these ranchos are

of the permanent type incorporating some concrete or other substantial

building material (Sanchez C6rdova 1973; Sadove 1973, 30; Turner 1967,

168; Vernez 1973, 23, 61).

In 1969, almost half of all public investment in new construc-

tion was made in loans to state-owned but decentralized (so-called au-

tonomous) financial institutions which spent about RD$ 2 million out

of RD$ 80 million on housing. These loans had to be secured, and they

were issued to recipients who had dependable, stable incomes, usually

the middle- and high-income residents, not the unemployed or under-

employed poor (Academia de Ciencias de la Rep6blica Dominicana 1977).

Government efforts to expand low-cost housing construction, ini-

tiated in the late 1950s, faltered during the mid-1960s and have since

tended to favor the small portion of the urban low-income population

that has secured reliable employment and is able to afford public hous-

ing remote from the commercial and industrial areas of Santo Domingo

(Vernez 1973, 95-100; Fanger 1978, 26-27; Crassweller 1966, 373-374).

Aspiring middle-class residents are following the same pattern as

extension of urban infrastructure underwrites more distant development

(Vernez 1973, 28; Kaiser and Weiss 1968, 57-58). As the population of

bureaucrats, business people, and technicians, who comprise the middle

class, expands, suburban development is expected to occur, but presently

they are often the occupants of public housing (Sadove 1973, 29;

Turner 1967, 167-168, 179; World Bank 1972, 30). The use of interior

space, the choice of location, the cost and the financing arrangements

for mortgages, have contributed to making public housing unacceptable

to or unobtainable by low-income families.

In 1970, RD$ 89 million in public funds were spent on construc-

tion, but only 3.5 percent was for new housing, much of it in the capi-

tal. By 1975, public expenditures for all new construction was

RD$ 251 million, 68 percent for housing (a cost-of-living index at 100

in 1969 rose to 188 at the end of 1975). In addition to losses due to

inflation, land speculation and widespread corruption within the con-

struction industry absorbed substantial proportions of the RD$ 31.6

million committed to the capital's share of new housing (Academia de

Ciencias de la Repdblica Dominicana 1977; Bell 1981, 187-189). Since

that peak housing construction year, rising fuel prices and high infla-

tion have curtailed public investment in housing.

Denied access to either the government or commercial housing mar-

kets, the poor people in most Caribbean cities have shared cramped

quarters with kinspeople and erected shacks throughout the city. Often

such spontaneous or self-help housing is built on land owned by the

government or in squatments where ownership rights are blurred. Such

settlements may have few if any municipal services (Turner 1967, 168;

Alonso 1964a; Havens and Flinn 1970; Vernez 1973, 12).

It is true that marginal housing is being replaced by other kinds

of housing. Since public funds loaned by autonomous financial agencies

tend to go to the construction of high- and middle-income housing, urban

renewal in Santo Domingo resembles renewal in U.S. cities during the

1960s and 1970s. The deteriorated areas were demolished, some to be

rebuilt in high-rise and expensive apartments, others to remain as open

spaces. In either instance, poor residents were displaced, forced to

move into other neighborhoods. The new residents increased demands on

already inadequate services and facilities, and higher densities led to

more congestion. Further deterioration often resulted in these communi-

ties (Bourne 1981).

Because urban land is limited, there is a tendency toward higher

density settlement in rapidly urbanizing cities. Much of the growth of

Kingston's population lives in densely settled, substandard housing

either in the center city slums or in peripheral marginal housing areas

(Clarke 1975, 96-97). It is believed that one-quarter to one-half of

Santo Domingo's population lives in downtown tenements and dense neigh-

borhoods at the city fringe (SAnchez C6rdova 1975; Fanger 1978). Follow-

ing the 1975 hurricane that flooded and devastated a large expanse of

marginal housing on the Ozama River floodplain, a plan was proposed to

resettle about 100,000 people living in a community illegally sited on

the bank of the river.

There is the belief in Caribbean capitals that squalor constitutes

the prevalent condition in marginal housing areas although there is

clearly difficulty in determining what standards ought to be applied to

defining substandard housing. Often the official position reflects

values that are unrealitic and hardly shared by the bulk of inhabitants

of these cities. Recent Dominican governments have been concerned about

the increase in people who are unemployed or underemployed and living

in the marginal settlements. Especially during elections, attention

has focused on these inhabitants who participate in the political pro-

cess (Bell 1981, 92, 124). But Latin American ecological research pro-

poses that the urban poor are not a homogeneous group and have varying

socioeconomic status and life-cycle stages which can be identified in

particular urban patterns (Gans 1968, 210; Alonso 1971, 4; Gilbert and

Ward 1978, 302-303; Turner 1968, 369; Mangin 1967, 68; Corten 1965, 5;

Souza and Porter 1974; Herbert 1973; Saf6 1974).

Turner (1968) considered the housing needs of low-income, low-

status inhabitants of several Latin American cities. Two patterns were

consistent. The poorest, usually the more recently arrived in-migrants,

were usually young, single, and with few marketable skills. They were

dependent upon accessibility to the employment opportunities in the

central business district and in the homes of middle- and upper-income

families. Given time, many of the inner-city poor acquired sufficient

experience to be employable in skilled, even permanent work. The re-

sulting improved economic condition permitted marriage and a family; the

new life-cycle stage required more living space. In the poor family,

however, housing is the largest proportion of the urban family's bud-

get expenditure (Sadove 1973, 29-30), and the minimum "low-cost" home

is beyond reach, so there is little opportunity in the commercial mar-

ket to acquire the needed space. Unlike the low-cost public housing in

Anglo-American cities which offers an alternative to the poor urbanite,

middle-income Caribbean families, caught in an extremely tight housing

market, have monopolized such housing. The result is that the poor

family must house itself by building marginally adequate homes on land

that is owned by others. In Santo Domingo, perhaps one-half of the

poor have moved into self-built homes (Sadove 1973, 29; World Bank

1972, 41; Bell 1981, 188).

There are at least three types of illegal housing settlements:

(1) those built on private or public land invaded by people who have

made no payment for its use; (2) the "pirate" housing areas constructed

on land sold in lots, legally, by entrepreneurs who have disregarded

municipal development codes that specify that basic infrastructural

services must be installed first; (3) the rentals erected by specula-

tors concerned for their otherwise vacant city land that is exposed to

possible squatter invasion (Turner 1967, 1968; Mangin and Turner 1968;

Mangin 1967). Whereas the third type is often a single house, the first

two types tend to occur at the city's edge in massive communities that

are often adjacent to middle- and upper-income developments.

Marginal housing at the city's edge tends to be occupied by the

more economically stable of the urban poor. These urbanites may have

moved several times in the process of making a long-term commitment to

purchasing a lot and building a modest home. It is a "step up" for them

and represents a substantial investment in a more secure future (see

Usandizaga and Havens 1966; Flinn 1966; 12-20; Vernez 1973, 16-20;

Turner 1968, 359). These marginal settlements are, thus, agents for the

social advancement of the poor just as home purchase in the commercial

market is a status decision for the other classes. Such settlements

house a substantial portion of the urban population in societies which

are slow to change and have failed to pace urbanization (Eyre 1972, 395;

Herbert 1973, 48; Turner 1966, 508-509; World Bank 1972, 41).

In the central business districts of these cities, the increased

competition for limited space is gradually transforming the traditional

plaza. The old homes of the urban well-to-do are being converted into

commercial and professional offices; the demand for rentals is resulting

in their conversion into apartments and rooming houses. The upper-

income residents who once preferred the convenience and excitement of

center-city living,with its old churches, parks, and proximity to work,

are opting for luxurious and fashionable new homes being built in pri-

vate residential neighborhoods at the city's edge (Grubb and Phares

1972, 14; Johnston 1971, 311-312; Eyre 1972, 397-398; Schwirian and

Smith 1974, 327; Quijano 1967, 11). This suburbanization, however, still

remains a minor phenomenon in some Caribbean cities.

Brown (1970) and Uzzell (1975) have found that where services are

available in the inner city, low-income residents exhibit much more

stability. They have resisted the efforts of landlords to evict them

in order to renovate or remodel buildings to house even larger numbers

of people. Consequently, the more recently arrived poor may have to

look for inexpensive housing further from the city center. This has

been substantiated by Ward (1976) who found that newly arrived migrants

tended to settle in the older, established neighborhoods rather than the

inner-city tenements. Similarly, Vernez (1973) discovered that in-

migrants moved into rented rooms in poor neighborhoods scattered about

the edge of the city.

Thus, at the city's edge, there are usually three types of hous-

ing. They are publicly financed housing, the high-income housing, and

the illegal settlements. The first two types are more orderly uses of

the land and result in regular patterns that accommodate the local

topography and the use of the automobile for transportation. Their neigh-

borhoods have curving streets which contrast with the rectangular grid

of the old neighborhoods of the colonial city. The illegal settlements

often leap-frog vacant land adjacent to the central business district and

spread out haphazardly across large areas at the city's edge (Turner

1968; Amato 1970; Vernez 1973, 25).

Social planners of the mid-1960s reacted negatively to these mar-

ginal communities, thinking them undesirable, the results of pathologies

of lower-income people, and debilitating to the health of the moderniz-

ing city (see, for example, Bonilla 1964; Shulman 1968; Berckholz 1963).

The prevailing belief persisted that home ownership is the major mechan-

ism for maintaining family ties and controlling social disorganization.

Furthermore, the prospective buyers of a home obligated themselves to

fixed monthly installments; occupants of marginal houses remain outside

the conventional world of planners and bureaucrats who wish to restrict

such residential land use. But public policies seeking to control mar-

ginal settlements have encouraged squatting. Slowly, officials have be-

gun to permit, even encourage, self-help housing constructed in areas

designated for planned "slums," in the hope that by doing so this can

preserve other open space for future development (Corrada 1969, 246).

There seems to be little doubt that marginal settlements at the

urban fringe have offered inner-city poor a way of improving themselves.


Given stable employment, the poor are willing to convert their wood and

cane shacks into concrete-block dwellings roofed with corrugated steel

sheeting and floor them in concrete. Continuing modernization is bring-

ing official acquiescence, especially legalization of claims to their

lands, and the introduction of municipal services-electricity, water,

sewers, street paving, garbage collection, police protection, schools,

medical clinics, etc.-over the years establishes and encourages these

communities (Turner 1968, 1976; Roberts 1973). There is much evidence

that land and home ownership are important values to the urban poor as

well as other, more fortunate city dwellers (Cornelius 1975; Lomnitz

1975; Stepnick 1979; Turner 1972, 1977; Mangin 1970).


People residing in the city pass through several stages during

their lives that involve changes in their living habits. These changes

are manifested in land use patterns. For example, the selection of

housing is associated with changes in life stages. People are likely

to leave behind the neighborhood in which they were brought up and even-

tually move to another residential area in the city which facilitates

their changing roles as spouse, parent, career person, retiree, and

elderly citizen.

Because of the intricate nature of the city, the evolutionary se-

quences of city forms have been premised upon key, large-scale variables

that include population, institutions, environment, and technology

(Berry and Kasarda 1977, 14). The geographic assessment of urban change

involves formal and functional relationships which vary importantly with

differences in scale. The formal city incorporates such diverse phe-

nomena as land use, settlement patterns, and population dimensions.

Urban morphology is assumed to be evidence of functional relationships.

Urban form is culturally associated, but it also contains patterns

similar to those in all cultural milieux. At some point in time, these

forms may tend to converge into a single, general pattern (see Hawley

1971, 290-315 for a discussion of the urbanization process in develop-

ing nations).

Social geography of cities can be traced to early work in areal

differentiation and man-land geography, both of which often viewed the

urban environment as one of economic specialization (see Whittlesey

and Wellington 1925; Hartshorne 1959; Sauer 1941). The little atten-

tion given to the characteristics of residential change was due in part

to the emphasis on the features of places rather than population charac-

teristics. But the improvements in national censuses and availability

of such data encouraged social scientists interested in a wide range of

noneconomic processes to explain urban morphological change. By 1930,

more Americans lived in U.S. cities than in the countryside. Cities

had become the centers of change, and it increasingly became popular to

search for ways to innovate in shaping this growth.

The social differentiation of the city into patterns of concen-

tric zones that have spatial identity was founded on the work of early

sociologists Robert Park, Louis Wirth, and Ernest Burgess. Homer Hoyt

proposed a second, sector model; both the sector model and Park and

Burgess' concentric zone model were modified by others including

Chauncey Harris, Edward Ullman, and Amos Hawley, but these first two

models remain the "classical" explanations of urban morphology and

ecological differentiation. It is likely that they are not contradic-

tory but rather represent stages in city growth. Thus the concentric

zone model emphasizes change during a period when the city contains

many population groups at various points of assimilation. The sector

model describes residential patterns of cities that have progressed

further along a continuum of ethnic assimilation when prestige or

status become a significant determinant (Herbert 1973, 74). With

continued city growth, Harris and Ullman proposed that the relocation

of economic activities and population movement was fundamental to the

formation of multiple urban nuclei within the context of metropolitani-


Concentric Zone Model

The Park-Burgess concentric zone model, resembling a nineteenth-

century model of an agricultural market town devised by von ThUnen, was

influenced by the work of Hurd (1903) on central and axial urban growth.

Park and Burgess used the nonhuman ecological concepts of invasion and

succession through competition and dominance to explain human community

use of space (Burgess 1925). Thus the city was seen as a product of

environmental competition and interdependence characterized by the social

and geographic mobility of its heterogeneous population. Change in the

location of people and institutions and the subsequent social reorgani-

zation were explained as concentric circles delimiting zones of homo-

geneous socioeconomic level, density, and distance from the center of

an idealized city. The gradient, developed by Duncan and Duncan (1955,

396) became the model's index of centralization. A negative value indi-

cated a tendency for the group to be concentrated beyond the center of

the city; a positive value suggested a trend toward centralization.

The model is an application of the distance-decay principle of centri-

petal force inversely proportional to distance based upon inductive

generalizations about forces responsible for mobility in the city

(Burgess 1923; Park and Burgess 1921; Park 1925).

It has been shown that these zones are not as homogeneous as

Assuming equal accessibility in all directions, Park and Burgess

measured distances in units of time and cost (Quinn 1940, 212). Social

distance resulting in a circular ecological structure could thus be

consistent with a rectangular spatial configuration in which accessi-

bility would be determined by a network of intersecting streets at

right angles.

Urban land, aggregated into four grades, was found to group into

concentric bands that were hypothesized to be internally homogeneous.

These were called zones, four of them encircling the commercial center.

In the central business district (CBD) is found the retailing establish-

ments including the main department stores and the chic specialty shops,

the central offices of major financial institutions, office buildings,

clubs, the headquarters of civic and political organizations, the

more expensive hotels, theaters, and museums. At the outer edge are

wholesale businesses including markets, light industry, and warehousing.

As the most accessible area, and with the largest daily number of trips

into and out of it, this zone contains the main transportation terminals.

Although when the city was youthful and growing this area was the site

of many fine residences, growth with increasing functions and result-

ing competition for limited space has left only a few pockets of hous-

ing which are much deteriorated and occupied by transients.

The second zone is adjacent to the wholesale district. Originally

the main suburban residential area for the city before the advent of

rapid transit and the automobile, it has been experiencing changes in

functions characterized by encroaching business and industry from the

CBD replacing the deteriorated housing. Landlords are either unwilling

or unable to maintain the tenements and remodeled houses. Neighborhoods

have changed and the few homes are badly outmoded. The rentals, in

tenements and rooming houses, are densely occupied by the newly arrived

migrants who are often unskilled, the very young and old, and survivors

of broken homes.

The independent working people occupy modest homes in the third

zone. These people desire proximity to employment in enterprises close

to the CBD, and they have had to trade off the amenities of living

further from the congestion of the city center for this accessibility.

However, the continued expansion of the CBD and the influx of new workers

tend to intensify land use in this zone, with the result that some of

the more fortunate in this area will invade the less dense, more de-

sirable residential areas farther from their present homes.

In the fourth zone are the homes of the middle class, people who

own and operate the smaller businesses of the city, the clerks and sales-

persons, the professionals who comprise the middle class in U.S. society.

There is no distinct boundary separating this from the next, outer zone,

unlike its other border contiguous with the working peoples' zone. For,

beyond this residential area can be found the small towns and hamlets

that are the dormitory suburbs of the city and in which reside high-

income commuters and their families. These commuters have chosen to

live here on the weekends, in segregated neighborhoods, and commute to

city-center jobs in long, daily trips or live in city-center apartments

during the work week.

Burgess identified two zones beyond the built-up area of the city.

The far-reaching agricultural district is within commuting range of

the city, while the hinterland extending beyond it still is linked to

the metropolitan area even though too far away for daily commutation

(Burgess 1930, 181-182).

The model assumes that urban population growth is due primarily

to in-migration, especially of low-income people seeking economic and

social improvement. This urbanization results in segregated housing as

the residential land use expands and new housing development occurs.

Newly arrived migrants tend to settle in the transition zone tenements

and rooming houses where rents are cheap, but densities are high and

conditions are often squalid. As in-migration continues, the housing

opportunities become scarce, both because of increased population and

the loss of structures to other land uses. Gradually these people are

forced to invade nearby low-income housing that has been vacated by

families seeking better homes farther out from the city congestion.

Thus, the process of change occurs on a gradient, the oldest urban

development closest to the CBD. The oldest neighborhoods are gradually

changed by this process of intermixing and sorting out that once again

establishes neighborhood stability with a different character.

Unfortunately, the condition of neighborhood homogeneity is con-

tradictory to the notion of a gradient in the value of social attri-

butes. Discrete, homogeneous concentric zones conflict with gradations

in income level, population density, etc., and human ecologists have

demonstrated that socioeconomic status increases with distance from the

center of the city. The model assumes that population density de-

creases from the inner to the outer zones. Dwelling unit density and

the percentage of home ownership have been found to increase with

distance from the CBD to the zone of most recent growth (and in the

1930s, this was 11 to 13 kilometers); beyond, both housing value and

ownership were found to decrease (Blumenfeld 1954). As the growth edge

moves outward, it carries the greatest concentration of activity and

experiences the most rapid rise in population density.

As long as the pressure for expansion and the resistance to inva-

sion are uniformly dispersed across the urban landscape, isochronal

lines of zonal growth move out from the city center in a circular pat-

tern. The pressure for housing in one zone leads to pressure on the

adjacent, outer zone, and each is transformed as people invade from one

zone to another.

The concentric zone model is a special case of a city with a cen-

tral business district, with sufficiently large population to permit

functional heterogeneity distributed in relation to work opportunities.

In that major employment center, city functions operate in a market

economy at the industrial/developed stage including the segregation of

activities based on minimum levels of accessibility. The older and

larger the city and the less active the growth, including the annexation

of new territory, then the more likely the "expected" pattern of the

concentric zones will occur (Schnore 1967).

Modernization has modified the conditions upon which Park and

Burgess formulated their model. The massive impact of automobile use

since World War II has greatly increased the extension of urbanized land,

has been directly responsible for strip development, and has made mul-

tiple centers of commercial activity necessary (Angel and Hyman 1972;

Richardson 1976). In some European cities, for example, the relocation

of industry near a source of cheap labor left the center of London,

Paris, and Moscow to the elite, while the poor were relegated to periph-

eral land on the outskirts of the cities. These patterns persist even

today in spite of post-war modernization (Hauser 1968).

There are topographical impediments to development in most urban

sites. But there are also such obstacles as historical inertia and

policies that tend to distort the ideal pattern that the concentric zone

subsumes. Thus, the functions which in a previous time were useful for

controlling change may persist even though they have ceased to be so.

Municipal ordinances may curtail certain kinds of growth. Vertical

space can become more important than horizontal space in the city that

has spread out so much that accessibility is at a premium and must be

stringently regulated. However, land use controls may not include air

rights protection nor encourage rational vertical development.

The Applicability of the
Concentric Zone Model to the Caribbean

In spite of criticism of the model, the concentric zone model re-

mains the principal paradigm explaining urban growth. Enough evidence

has yet to be collected, however, to assume the Caribbean capitals,

with continued growth and development, are evolving as suggested by the

idealized model. There have been some cross-cultural comparisons made

with Anglo-American and Asian, African, and Latin American cities (see

Hansen 1934; Hayner 1946; Caplow 1949; Dotson and Dotson 1954; Hauser

and Schnore 1965; Schwirian and Smith 1974; Clarke 1974; Schwirian and

Rico-Velasco 1971; Turner 1968, Mangin 1967; and Alonso 1964b for Latin

American research).

From a study of the literature about ecological patterns in Latin

American cities, Schnore (1965) concluded that there is an evolutionary

process of urbanization including residential patterns indicative of

social differentiation. The socioeconomic status of neighborhoods

gradually changed with development to assume the concentric zone con-

figuration. In the more traditional cities, the higher-status group

preferred city-center residences; however, with modernization (and all

of the cities displayed change in this direction), the upper class

vacated their older city residences for new homes built on larger land

parcels at the city edge. Schwirian and Smith (1974) found that in the

smaller Puerto Rican cities, social status was negatively associated

with distance from the CBD, while in San Juan, there was a reversal of

this pattern as well as decreased density of residential neighborhoods

with increasing distance from the city center. Clarke (1974) found some

evidence for the same patterns in Kingston; however, there did not

appear to be a commuter zone, and the transition zone was difficult to

demonstrate. The social status gradient held true generally except for

the peripheral "shantytowns" and public housing developments (Clarke

1975, 132).

Turner (1968, 359-360) considered the applicability of the Park-

Burgess model to low-income, low-status housing in Latin American cities.

Two patterns were consistent: The inner area in the zone of transition

which houses the poorest and the newly arrived followed the model; an

outer, peripheral area of poor inhabitants exists, however, which is

inconsistent with the concentric zone hypothesis that proposes a com-

muter zone of well-to-do residents. Turner (1968, 360) labeled the

inner-city poor as bridgeheaders, and described them as barely skilled,

largely unemployed upon arrival,and dependent upon the few jobs to be

found in the central city businesses and in the homes of middle- and

upper-income residents. Turner identified another group at the perimeter

of the city as consolidators, poor people who had apparently secured

more permanent employment and were able to forego city-center proximity

to improve their housing situation.

Such research, which seems to conflict with the concentric zone

model, in fact, may not indicate that the model does not apply to Latin

American or Caribbean cities. Evidence exists for an evolutionary se-

quence in the development of urban residential structure. Schnore (1963)

computed the age of Latin American cities from the decade in which they

achieved 50,000 in population, concluding that it appeared the best pre-

dictor of urban spatial structure. The smaller, and thus younger, city

was likely to have high socioeconomic-status people living in the city

center. With time and increased population, decentralization becomes

pronounced: the middle class often establishes residence at the urban

periphery first, but, once its numbers become sufficiently large, is

soon followed by the upper class. Schnore attributed the differences

between young and old cities to the nature of the housing market. In

central cities' older areas, there are many obsolete buildings, whereas

in young cities without such older, inner neighborhoods, there are many

high-status buildings because decentralization has not been present

long enough to encourage extensive growth of a transition zone. With

such growth and expansion of the urban core accompanied by improved

accessibility, the upper class will vacate the center city, leaving

behind their homes which are modified to accommodate low-class residents.

Schnore (1964) pointed out that larger, older cities which used

annexation less often to accommodate growth were more likely still to

exhibit the expected concentric zonation. Thus, the more rapidly grow-

ing the urban center, the less likely that concentric zones will per-

sist; the older, larger cities display the most apparent Park-Burgess

concentric zone pattern.

Although Davis (1969) disagreed with Schnore on the sequence of

out-migration from the city center pressured by urbanization, both

researchers concur in an evolutionary model of residential change that

consists of four stages. There is a preindustrial stage when the city

is small and growing slowly. The elite resides adjacent to the central

business district. In the industrial take-off stage, urbanization is

accompanied by transportation innovation promoting improved accessi-

bility. The upper class is able to move to the edge of the built-up

zone. The lower class dominates the inner zone, and the middle class

is left intermediate to these two. In the third stage,which is a

continuation of industrialization, increased pressure for change in

residential areas is prominent. A new elite, emerged from prosperity

based on industrial expansion, can afford and demands new, luxurious

housing. Innovations in housing technology result in obsolescence.

As the process of occupancy change called filtering permits other,

less affluent people to occupy once high-income homes, a pattern of

decreasing status toward the CBD results. The general prosperity

encourages expansion of the middle-income group and leads to more clearly

defined zones of socioeconomic level. The fourth stage is postindustrial,

characterized by stable residential patterns. Growth is most conspicu-

ous in middle-income suburbia which encircles the older, high-income

area at the fringe of the city's built-up land.

In studying Latin American cities, Amato (1974) failed to identify

a middle-income group intermediate to an inner-city, low-income zone

and a suburban high-income zone. Rather, the elite lived in low-

density, dispersed neighborhoods, all of which were approximately equally

distant from the center city. The middle-income group lived in closest

proximity to the CBD at relative high density, suggesting their willing-

ness to exchange space for accessibility. The low-income neighborhoods,

also relatively dense, were more dispersed and at locations farther out

than the middle-income neighborhoods.

Individual urban communities, i.e., inner suburbs and outer sub-

urbs in a metropolitan area, may also differ in development stages at

any particular point in time. Wils (1974) suggested that it is possible

that urban conditions measured during recent censuses, for example, may

reflect a single stage of development. Thus, studies of Latin American

cities restricted to very recent data collections may fail to support

an evolutionary model of urban spatial structure only because the

period of information gathering is short by comparison with the Anglo-

American research base of census data extending well into the nineteenth

century for many coastal cities. If a general theory of urban spatial

structure is to exist, then researchers must consider the possibility

that cities may be at various development stages and moving toward

experiences similar to those of Anglo-American and Western European

cities. Preindustrial cities do not display as clear a differentiation

of residential neighborhoods according to socioeconomic and life-cycle

status as do postindustrial cities. Comparative studies of spatial

structure in other cultural milieux are needed to substantiate present

theory (Herbert 1973, 178-179; Abu-Lughod 1969, 209-211). As

Johnston (1971) stated in his review of the literature of urban spatial

patterning, the concentric zone model is incomplete and contradictory.

The effect of population growth and modernization on the urban fringe

remains unclear to him as well as to students of Caribbean urbanization.

Sector Model

Hurd (1903, 59) noted that city growth was evident in two patterns,

central and axial, which ranged outward in all directions from the city

center provided there were no impediments to development. Such growth

tends to parallel transport lines, making adjacent land more valuable

because of improved accessibility. The evolutionary character of growth

results in the obliteration of the physical evidence of unequal growth

in the immediate advance of central growth, but a star-shaped configu-

ration persists in the wake of axial expansion ahead of the main city


In the 142 U.S. cities which Homer Hoyt (1939) examined, railroad

and water transportation routes attracted industry, and local residen-

tial growth accompanying industrial expansion tended to extend out from

the center of the city in a wedge-shaped pattern. The prevalent wind

direction carrying industrial airborne pollutants reduced the desira-

bility of land in its path for residential use. Land that escaped this

pollution was sought after, often by the well-to-do; once established,

the high-income neighborhoods tended to remain homogeneous as they

expanded outward within a sector bounded by transportation corridors

(Hoyt 1939, 53-58). A slowly urbanizing city was expected to have much

central expansion and less active axial growth and fewer outer settle-

ment nuclei along transport lines. A rapidly growing city, by con-

trast, would expand overall, intensifying land use in both axial and

central development including filling in during this growth process.

Residential land use intensification included vertical growth and

the change from single- to multiple-family, higher-density structures,

the development of what had been vacant land, and the outward exten-

tion of the city perimeter. Hoyt (1939, 69) identified the high-rent

residential area as the initiator of expansion and the force attract-

ing all other housing on a gradient of rental based on land value; the

gradient sloped downward in all directions from it. Originally sited

near the retail and office center which was close to employment and

usually far from industry, the high-income residential sector encom-

passed a relatively large area for the number of people housed within

it. But the desire for upgraded neighborhoods, modern living condi-

tions, little or no congestion, and other beneficial attributes induced

people with means to relocate farther out along nearby transportation

corridors which provided accessibility and rapid journey-to-work routes.

Often these routes extended to more distant commercial centers.

Usually the best land was selected for the high-income housing.

It was best when sited at a high elevation, commanding a fine view,

safe from flooding, and accessible to cooling breezes. The best land

could be found along unspoiled waterfronts, and wherever there were few

natural barriers to transportation. Such land, once established as the

upper-class residential area, with continued urbanization would even-

tually extend outward in a wedge from the CBD. The direction of this

expansion resisted change although real-estate promoters were known to

modify the trend by convincing city leaders to relocate elsewhere out-

side the sector (Hoyt 1939, 69-71).

In the portion of the sector closest to the CBD and which was

being filled in change persisted. Luxury apartments were built on

cleared residential land. Immediately adjacent land on either side of

the sector tended to accompany outward extension of the wedge. At any

distance from the city center, mutually exclusive activities competed

for space, i.e., manufacturing concerns and multiple-dwelling struc-

tures, but inertia helped to preserve the integrity of the sector's

homogeneity in both social class and land use. In the ideal form of

the model, Hoyt proposed that the sector was actually heterogeneous due

to invasion and succession which modified the land use intensity. Thus,

for example, the upper-income sector would include specialty shops

catering to its well-to-do customers, expensive high-rise apartments,

older luxury apartments, elaborately constructed homes,and those indus-

tries such as hospitals and laboratories which employed professionals

who could afford to live in these communities.

The Applicability of the Sector Model
to the Caribbean

In a later assessment of the sector model's applicability to

Latin American cities, Hoyt (1963) found that single-family homes of

the elite and their luxury apartments tended to concentrate in one side

of a city. The sector model incorporates a growth process for expan-

sion of the sectors. Increased demand leads to development that is

simply added to the outermost portion of the wedge. Thus, as Latin

American cities became crowded, urbanites migrated outward from the

center city to new housing constructed at the urban edge but within a

sector already established as predominantly homogeneous in socio-

economic status. Amato (1974) demonstrated that Bogota was continu-

ing to develop along the same sector pattern identified by Hoyt. The

elite remained on the east side of the city opposite the industrial

development. Vernez (1973) found, however, that marginal housing

settlements competed for land at the periphery of Bogata,and assumed

that over time there would be further evidence of the trend toward

heterogeneous residential growth. Nevertheless, he concluded that

Bogata was growing "somewhat along the lines of Hoyt's theory of urban

development" (Vernez 1973, 22).

The sector model suggests that high-income residents are the

trend setters and the most important participants in residential land

expansion, establishing both the timing and direction of growth. In

both Latin American and Caribbean cities, new residential areas often

exhibit California-style ranch homes built in closed developments that

include shopping centers, churches, private schools, and extensive

street networks. The occupants were once inner-city residents who lived

in colonial mansions since remodeled as multifamily units and occupied

by middle-income renters.

The expansion of elite residential areas often occurs along higher

elevations where climate and view are best and where the homes are most

distant from the noxious industrial and commercial activities. Portes

(1977, 68-69) concluded that isolation and space are as important to

the Latin American elite as they have been to the well-to-do in Anglo-

American cities. Once ensconced in their exclusive communities, they

are served by fine highways and paved streets, municipal services, and

private commercial and professional services. Increasingly, sharp

divisions along socioeconomic lines are segregating Latin American

cities (Portes 1977; Gilbert and Ward 1978).

Economic growth in Latin America since World War II has included

expansion of management opportunities and the professional services,

resulting in growth of a middle class (Gilbert and Ward 1976, 287-288).

These urbanites have access to most social services, consumer goods,

recreation, and good housing.

Aspiring, middle-income urbanites in Latin America have been

found to seek out housing close to the elite sector (Johnston 1971).

Besides the status which accompanies residence in such neighborhoods,

there are substantial advantages to middle-income communities which

are able to utilize the transportation system servicing the elite as

well as municipal services extended to the homes of the well-to-do at

the urban fringe. Since middle-class renters occupy the remodeled

center-city mansions left by migrating high-income residents, Gilbert

and Ward (1978, 295-298) have concluded that this socioeconomic group

is becoming a major influence in determining residential patterns in

Latin American cities.

Much criticism of the sector model has centered on its descrip-

tive nature (Firey 1947, 86). It is believed that cultural and social

explanations exist for human adaptation to physical space. Thus, loca-

tional behavior is directly determined by the values of the social

milieux with associated activities the result of rational assessment of

the environment. Alonso (1964b, 227-231), in a reinterpretation of the

concentric zone and sector models, dismisses them as historical explana-

tions. Rather than accepting the processes of invasion and succession

for the changing socioeconomic patterns, he offers a structural hy-

pothesis which assumes neighborhood choice is a result of one's prefer-

ences. Such a criticism appears to ignore Hoyt's emphasis on choices

made by social groups as determining residential site selection and

thus patterns of urban morphology.

Multiple Nuclei Model

The most desirable points in a city are often those most accessible

to other points. On the theoretical economic plane, that locus is the

central business district, ignoring the influences of speed and mode of

transport (Odland 1977, 3; Hamburg and Creighton 1959, 68). The CBD is

assumed to draw the labor force to the major employment opportunities.

These lines of communication include numerous points of unusual activity,

i.e., breaks on transit lines where there are connecting routes or

changes in the mode of transport. At these sites, establishments

serving the commuters will proliferate. Over time the agglomeration

attracts more activities until the emerging node may include industry,

businesses, schools, residences, recreation facilities, etc. At the

center of such diverse activities, a node becomes stable and begins to

generate its own traffic, thereby contributing to the growth of a city.

Such expansion in a series of many nuclei is the contribution that

Harris and Ullman made to understanding urban spatial structure (Harris

and Ullman 1945, 14-15; Mayer 1969, 33; Hamburg and Creighton 1959, 68).

The initial nucleus in a city will have been based on such func-

tions as defense, transportation, administration, education, religion,

mining, manufacturing, recreation, marketing, etc. But the appearance

of separate nuclei is due to one or more of four conditions. Certain

activities require specialization, others profit from cohesion, still

others experience exclusion because their activities are detrimental

to neighbors, and, finally, there are activities that cannot afford the

more desirable locations and must opt for remaining space (Harris and

Ullman 1945, 14-15).

Multiple nuclei, therefore, tend to be homogeneous in their func-

tions, at least during their initial formation. They are also primarily

phenomena of the metropolitan area rather than the central city

(Anderson and Egeland 1961, 394). Beyond the central business district

where accessibility is less and rents are lower, a wholesale and light-

manufacturing nucleus may develop along a transportation route at a

crossroad. A heavy-industry district may be sited at the edge of the

city. The cultural and entertainment centers and outlying business

districts may become other, minor nuclei. The residential district re-

quires some measure of accessibility, but is selective of topography and

nuisances (Harris and Ullman 1945, 15).

It is likely that Anglo-American cities and their metropolitan

areas have manifested aspects of all three models of urban spatial

structure. The zonal model has been confirmed as characteristic even

where sectoral change dominates (Johnston 1971). In most cities, how-

ever, there is a clear sector patterning of socioeconomic status of

the urban population. Berry (1965, 100) concluded that the three models

contribute independently to the understanding of the socioeconomic

structure of neighborhoods. Herbert (1973, 74) proposed that the hy-

potheses may represent stages of growth. The concentric zone model

represents the early stage when the city was more homogeneous in popu-

lation and activities. Development and the reduction of social dis-

tance caused the neighborhoods to expand sectorally. Eventually a

multiplicity of activities and the extension of transportation corri-

dors induced the competition of other centers.

The Applicability of the Multiple Nuclei Model
to the Caribbean

Since multiple nuclei are primarily associated with large cities,

it is apparent that in an evolutionary scheme explaining land use change,

the city will have had to experience extensive development for condi-

tions to have occurred that made multiple muclei possible. Thus, the

city that experienced both vertical and horizontal expansion would most

likely exhibit such a configuration.

When models fail to predict spatial structural change, reasons

include modifications of the present market system, the introduction of

some artificial constraint on free-market forces of supply and demand,

or the slowing down of urbanization. Increasing governmental interven-

tion including such regulatory policies as planning and zoning ordi-

nances can modify the expected zone or sector change. Even the spread

of prosperity to other urban groups can result in decreasing social

distance and cause residential neighborhoods to become heterogeneous

(Robson 1969).

Johnston (1971, 195-196) noted that a major criticism of socio-

economic evolutionary urban models of residential land use is the

failure to account for cultural values that are important for indi-

vidual examples; however, on a broad scale, these three hypotheses of

urban spatial structure may serve as a baseline for generalizations

about urban change.

An essential research area that remains to be adequately explored

is the applicability of these theoretical constructs on a cross-

cultural sweep, for general theory building requires that behavior be

predictable under universally measurable conditions. In consideration

of the common Western heritage and interaction among peoples of North

American, it should be possible to expand our knowledge of urban experi-

ences that share interregional similarities. Identifying such common-

alities is a necessary step in isolating and identifying the general

causes of urban change. Planning for this change in the Third World is

becoming critical under the mounting pressures of urbanization in the

Caribbean and Latin American and the future likelihood that the phe-

nomenon will spread to Africa and the Far East. In the Caribbean as in

the rest of the developing world, limited space and scarce resources

will permit few mistakes in preparation for the societal changes that

will accompany urbanization.


Aerial Photography Data Base

In addition to being the largest city on the island of Hispanola,

Santo Domingo is the regional capital and administrative seat of the

National District which extends into a rural hinterland well beyond the

metropolitan area. Local conditions and associated problems of a

large city are of concern to officials of the municipality, but their

proposals have not often taken precedence over regional and national

considerations involving city resources. The need for boundaries which

help define responsibilities of city departments and limit urban in-

frastructure has been recognized by national leaders. In September

1975, President Balaguer submitted a national commission's proposal for

the city's future growth to the National Congress which included a

message in which he explained that such a plan was needed to stem the

horizontal spread of Santo Domingo.

The proposal included 16 articles, the first of which defined the

city borders which enclosed an area of approximately 80 square kilo-

meters. The third article called for the periodic revision of these

limits, while the fourth specified the need for an inventory of land

use. The most politically sensitive issue addressed in the proposal

was the suggestion that land developers would have to pay for the exten-

sion of municipal services beyond the city borders.

For purposes of this research, the study area was extended be-

yond the national commission's recommendation in order to include

developed land that appears on the aerial photographs as linked to the

urban communications network and is close to the contiguously built-up

city. The preliminary study area was 16 kilometers wide, stretching

from the residential community of San Francisco in the west to Reparto

Isabelita in the east, and 9 kilometers from the Caribbean coast to the

Isabela River at Puente de Pontones. The site is about 144 square

kilometers and is outlined in Figure 4-1.

Temporal and Spatial Framework

The aerial photographic coverage in 1948 and 1974 was selected

for interpretation. Prior to World War II, most of the urbanized area

was confined to the colonial center and contiguous land to the north

and west of the old city walls, and included the communities of La Fe,

Mejoramento Social, Naco, La Esperilla, and Villas Agrfcolas. There

was little development on to the east bank of the Ozama River, and the

large airport impeded extension at the western edge. The earliest

postwar photography, in 1948, was chosen as the base year for analyz-

ing land use change in order to demonstrate the city's spatial patterns

shortly before extensive areal growth occurred. The 1948 photography

reveals a city limited to an area contained between the Andrews Air

Force Base in the west and the Ozama River in the east, with a few,

scattered buildings along the eastern bank of the river. The popula-

tion of Santo Domingo is estimated to have been less than 250,000 in

that year. The colonial center and the area to the north, in what

was once a rural village called San Carlos, are the most clearly


4,s' g I

44 W .


.1 *, ~
__ _ __ _ __ _ __ _ U." I I i

defined developed areas. The transportation network does not extend

much beyond these except as unpaved streets with widely dispersed

houses. Undeveloped plots are scattered throughout the build-up city

lying outside the colonial walls.

In 1974, there were three times as many people living in Santo

Domingo which covered an area five times as great. The airport had been

removed, eliminating a major impediment to growth to the west. Paved

streets, two new bridges which replaced the single span over the Ozama

River, and portions of a circumferential highway were in evidence. Al-

though there appeared to be less open space interspered with developed

land, there was much undeveloped land at the edge of the built-up city.

Since land use information obtained by sampling the city was to

be correlated with that obtained from the analysis of the aerial photog-

raphy, it was necessary to devise a land use classification which would

permit interfacing the survey data with the type of development, and

indicators of socioeconomic level with the remote sensing information.

The aerial interpretation was structured so that the land use cate-

gories would coincide with the field survey land use designations.

There were three data bases: the 1948 and 1974 aerial photography and

the 1975 field sample of streets in the capital. All land use informa-

tion and a measure of distance from the site to a central point were

aggregated into one-hectare cells of a grid system centered at the

central business district. A 1973 city map of the transportation net-

work served as a base map. Figure 4-2 shows the steps taken to analyze

both the photography and field information. Interpretation of the

former data bases produced land use and land use change maps. The

Figure 4-2: Flow Diagram of Research Methodology

field survey included more than 140 streets and over 9,100 sites, all

of which were mapped. An overlay of hectare-sized cells was used to

sort the data which were merged with the aerial photographic data.

Factor analysis of residential land use produced three important fac-

tors defining socioeconomic levels of housing.

Five land use categories were selected: low-income residential,

medium-income residential, high-income residential, open space, and

other use, which was a combination of commercial, industrial, and pub-

lic uses. The aerial photography was interpreted before the field re-

sults were analyzed, and the field sample variables were taken into

consideration in establishing the residential land use groupings.

Mapping Criteria

Residential land use was segregated into three socioeconomic

levels based on a variety of conditions which were included in the 1970

Population and Housing Census and which were believed to discriminate

among the broad income levels. Previous work by Thruston (1953),

Rapoport (1969), Cortdn (1965), Openshaw (1969), Amato (1969), Johnston

(1969), Eyre (1972), and Vernez (1976) suggests that there is a rela-

tionship between socioeconomic class and building materials used in the

homes constructed for the occupant families. For example, the

colonial-type house resembling the courtyard-centered structure familiar

throughout Spanish America can be found in Santo Domingo. A large,

several-storied, European-type house is found with a wide range of

exteriors dictated by style changes over the years. The American

ranch-style house is built by middle- and upper-income owners who

desire the modern conveniences which accompany these residences.

Popular, multiple-family housing for middle- and high-income

urbanites, often found in the center city in the form of high-rise

buildings, offers the advantages of convenience and excitement so im-

portant to those who relish city life. Another housing opportunity for

the middle-income families is public housing. Although ostensibly con-

structed for low-income families, nevertheless, public housing projects

often become middle-income neighborhoods whose relatively affluent

occupants, the bureaucrats, professionals, and technicians of a modern-

izing society,are much more desirable tenants than poor people with

tenuous salaries.

Low-income housing varies considerably. Single-family, low-income

homes are often simple, one-room shelters at first, usually no larger

than 30 square meters and constructed of wood, recycled materials, and

palm thatch. Subsequently, as the family income stabilizes, the occu-

pants may improve their homes. Wooden and cardboard walls are replaced

with concrete blocks, and the roofs are weatherized with galvanized

steel sheeting. The dirt floors of the original homes are covered with

cement. Cement is the most popular, least expensive building material

for improvements which may include the addition of a kitchen and bed-

rooms, and even space for a small business. Eventually, the lot sur-

rounding the homesite will be fenced to protect a garden plot. Over

several decades, the home may increase in size three to four times.

Community densities of 200 to 500 persons per hectare are not uncommon

in low-income neighborhoods (Vernez 1976, 9-11).

Large poor populations often receive the attentions of municipal

officials who were once disinterested in the problems of only a few

needy families. The older, more permanent low-income communities have

paved streets, curbing, sidewalks, schools, parks, and even sewer and

water connections. In Santo Domingo, for example, electrical service

is available throughout the metropolitan area and is the result of an

ambitious national hydroelectric development program that is provid-

ing extensive if unreliable electrical service to the city. Although

the lines may be illegally tapped, nevertheless, most low-income neigh-

borhoods have power.

The residential land use categories were finalized after con-

firming that these features of housing were visible on the aerial photo-

graphs. Land use was determined for each cell of a grid overlay of

hectare-size units positioned over the aerial photographs to coincide

with a grid of units of equal area drawn on a 1973 city map prepared by

the Geographical Institute of the Autonomous University. The follow-

ing characteristics were used:

1. Low-income residential structures are small, usually less

than 100 square meters; they have no landscaping and no evi-

dence of automobile ownership; roofs are constructed of palm

thatch or steel sheeting; they have few building edges

(indicating a small number of rooms); they are closely sited

with little or no open space between; they are close to a

rectangular network of streets and connecting, serpentine

pathways; there are few paved streets; there is frequent

irregularity in building alignment. Where the majority of

structures in the hectare could be so grouped, the use was

deemed low-income residential.

2. Medium-income residential structures have concrete, tile, or

asbestos roofs, there is much open space between buildings

indicating moderate to low density per hectare; the struc-

tures may be landscaped; the lots are often fenced but do

not include garden plots; there are driveways and carports;

there are many edges to the structures; there is a regular-

ity in the alignment of buildings and streets which often

form a rectangular grid.

3. High-income residential housing is significantly different

from the other two groups. There are very low densities,

often one large building to a hectare; the structure has

many edges, extensive landscaping, driveways and fencing;

it is found in areas that have rectangular and curving

street patterns that suggest much use of the automobile.

Terrain that is sloping is desirable because of the privacy

and ambience it affords, and the land is often heavily

wooded. There is a general absence of commercial and indus-

trial activity which includes parking for numerous automo-

biles, large buildings with few edges, proximity to well-

traveled highways, pollution, and little landscaping.

Other use was the category with the greatest variety of activi-

ties, including government, commerce, manufacturing, and any other

urban, nonresidential purposes. Indicators include high density of

very large, many-storied structures with only a few edges, proximity

to similar structures, much automobile parking space, extensive

storage area, evidence of congestion and pollution, accessibility to

transportation, large machinery, and absence of landscaping.

Open space is indicated by the absence of development. When over

half of the unit area had ground cover, did not have paving, and was

not included in the fenced site of a residence, then it was designated

as open space.

Aerial Photography Interpretation

The grid overlay was centered at the Parque Independencia, the

hub of the commercial center of the city, and each cell of the grid was

given coordinates of longitude and latitude. These coordinates were

used to compare land use over the 27-year period between photographic


While the 1974 photographs were scaled to the 1973 city map, the

1948 aerial photography required scale adjustments before a land use

map could be compiled. The 1973 map of the city was photographically

reduced to accommodate the larger scale of the older aerial photographs.

The information was transferred to the 1973 city map. A final reduc-

tion of the map was accomplished in order to scale equally both land

use maps for the land use analysis. As in the case of the 1974 land

use data, each hectare cell was coded for coordinates and land use, and

the data were stored for computer-assisted comparison and evaluation.

A final determination of the city boundaries was accomplished

following the interpretation of the aerial photographic coverage and

compilation of the 1974 land use map containing the location of each

hectare of land use. One procedure would have involved connecting the

"outside" edges of all developed land and designating this line as the

city perimeter. The resulting boundary would have approximated the

executive proposal included in the presidential degree of 1975.

To have used these limits, however, would have excluded some develop-

ment that is of much interest but would have lain beyond the contigu-

ously built-up area.

Land speculation is an important influence on urban development

in the Caribbean. Land ownership and the economic advantages of keep-

ing land undeveloped as the city expands are common in an island

economy that tends to be inflationary. The land use map for 1974 in-

dicated that defining the city limits on the basis of contiguity of

developed land would have excluded significant expanses of residential

land, including the marginal housing identified at the edge of the

city, such as the communities of Katanga, Puerto Rico, Mandinga, and

Villa Faro. The solution was to determine the outside limits of built-

up area that was larger than five contiguous hectares in a particular.

land use category. All such developed land was connected at its out-

side edges to form the city boundary.

Field Survey

A field survey was undertaken in 1975 to characterize housing

conditions in the city. The urban area was too large to permit a com-

plete investigation of all housing, and, therefore, a stratified,

unaligned random sample of housing was conducted. The sampling design

included 10 percent of all streets involving nearly 150 streets rang-

ing from a single block to many blocks in length (Figure 4-3).

Avenida S. Bolivar was included in the sample, for instance, and this

major thoroughfare extends from the Parque Independencia to the western

edge of the city. The investigation of all housing along these streets

provided reliable information about the number and type of structures,




















i U

the land uses, building construction materials, indicators of socio-

economic status of the occupants of residences, the condition of

streets including curbing and sidewalks, traffic congestion, and pollu-


A key objection of the research was to determine land use,

especially residential land use, and it was assumed that, controlling

for the independent influences of such factors as socioeconomic status,

each newly arrived city inhabitant theoretically could find housing

anywhere within the urban confines. The mix of residents was presumed

to result from independent decisions related to income level, education,

employment, life-cycle stage, family size, marital status, and similar

situations in which people exhibiting similar socioeconomic status

aggregate. There are socioeconomic differences when comparing a hectare

of high-income residential land use in the city center with high-income

status in residential land use at the suburban fringe. This research

effort is at a more generalized level, however, and seeks to identify

gross distinctions between residential land use whicn would allow com-

parisons to be made between Anglo-American and Caribbean urban land use.

The urban area of Santo Domingo is generally subdivided into lots

of about one hectare. Land is sold in square-meter increments. The

colonial unit of measurement of one solare was slightly more than 100

meters and the old portions of the city reflect a subdivision pattern

of blocks 100 meters in length. It was decided that the hectare, 100

meters in length, would be the most efficient measurement unit for the

field survey.

The sample size may be determined by estimating the population

parameters. For a degree of accuracy equal to 0.05 percent for one-

half of the normal curve, or a total interval width of 0.10, the

formula for estimating the population is

S 1.96 (o / /T).
0.10 = 1.96 o/ /N.
Solving for N, (1.96 01)2
N = (1.96 a / 0.1)

and a is to be estimated from the sample data. The estimate of the

standard error of the mean, a, is obtained from the Student's t distri-

bution. The degrees of freedom are since, for testing purposes, this

is nearly accurate. A level of confidence of 0.95 is acceptable; most

morphological research has had lower levels, and, although direction is

expected to be predictable, a two-tailed test will be used. Thus, at

0.95 confidence and a two-tailed test, the sample size will be

N = (1.96 8 / .1)2

N = ((1.96 x 1.96) / .1)2
N = 1,476.

The sample size would have to be 1,500 structures.

The mix of structures and land use in Santo Domingo is hetero-

geneous. A preliminary investigation of the city done by automobile

indicated that residential use was homogeneous on a block-by-block

basis, this regularity often continuing for many blocks along the

street. It is more efficient to use the stratified sampling proce-

dure where there appears to be greater homogeneity within than be-

tween aggregates (Harvey 1969, 352). Spatial sampling can include

random collection from an infinite number of points comprising the

area, or it can consist of a finite number of small area units which

make up the total.

The research includes sampling traverses that extended the full

length of any particular street sampled. Because of the linear trend

of development and of land use associated with the accessibility which

accompanies the networks of streets, pathways, and highways that dis-

sect the city, the stratified sample was based upon the city atlas pub-

lished by the National Police. A 10-percent random sample of more than

1,400 streets was drawn from the atlas. Each traverse was field sur-

veyed, structure by structure. The field survey measured 40 variables

including all structures, the external condition of the buildings, the

type of building materials used in walls and roofing, the number of

floors, the outward appearance including landscaping, evidence of

automobile use by the occupants, the additional activities of a com-

mercial or professional nature in a residence, the street conditions,

and whether the area exhibited congestion and deterioration. Each

block was determined by intersecting streets or the terminus and an

intersection. The information was recorded on tally sheets, similar to

Table 4-1, identified by the name of each intersecting street.

The purpose of the field survey was to group land use into five

general categories: residential, governmental, commercial, industrial,

and open,or underdeveloped. The residential land use category included

a seemingly endless assortment of housing types, especially in the

poorest areas of the city where almost any discarded materials would be

pressed into service as shelter. Apparently, building materials are

dependent upon the inventiveness of the occupants. Outside the

Table 4-1: Field Survey Instrument for Recording Land Use
and Building Conditions in Santo Domingo

Residential L
Single Family...-.........
Multiple Family ......... .
Apartment ..................
Improvised .................
Commercial ...... ..........
industrial .... ............
Open Space ....................

Concrete .......... ......
Cement Block..............
Wood ... ..............
Palm ....... ........
Galvanized Steel Sheeting...
Brick .......................
Limestone-Colonial .........

Concrete ....................
Galvanized Steel Sheeting..-
Asbestos ........ ..........
Tile ........................
Yagua-Cana .. .......... .

Number of Floors
One . ..................
One and One-Half ............
Two ........ ............ .
Three .......................
Four ........ ................
Five or More ...............

Landscaping .................
Recently Painted .............
Driveway ......................
Carport .............. .....
Louvered Windows ...........
Grated Windows ...............
Fenced Property ..............
Professional-Commercial Use..

Congested ...................
Sidewalks ...................
Curbing. .... ........... .
Pavement-Poor ..........
Clean ...................

/ II I
I .
r ry ~ i

I ~
r ~ --r'

marginal settlements, however, low-income persons tended to occupy long

wooden structures which housed four or more families, each household

possessing several rooms and a doorway facing the street. These

multiple-family structures contrasted with middle- and upper-income

apartments which more closely approximated those found in Anglo-

American cities. Whenever the structure varied from the single-family

residential home, it was necessary to determine its predominant use,

and this was accomplished by ruling out public, commercial, or indus-

trial activities, by interviewing the occupants, checking for multiple

mail boxes, listening for the sounds of playing children, looking for

drying laundry, observing pets roaming the hallways, and other manner

of information-gathering strategies.

Public housing was conspicuous for its uniformity. The national

government sponsored construction of urbanizaciones, or projects, which

were composed of housing types, e.g. "type A" or "type B." These were

blueprint structures that were found throughout the more recently devel-

oped sections of the city in public housing projects. Other middle-

income apartments were distinguished from tenements by their general

state of good repair and cleanliness, lack of open doorways and un-

employed, poorly dressed occupants, and absence of children, who were

assumed to be in school.

There was little difficulty in separating commercial from either

public/governmental or industrial use. In the downtown commercial cen-

ter, the main avenue was surveyed structure by structure on each floor,

and the dominant use noted. There were many structures in primarily

residential areas which included small stores or offices. Other

observations included whether there was evidence of fresh paint, an

indication of expenditures for upkeep which helps to distinguish low-

from middle-income housing. If, at the time of the survey of streets,

which occurred between 8:00 A.M. and 7:00 P.M., there were trucks and

buses passing along, if many cars were present, and if the consequent

noise made hearing normal conversation difficult, the street was deter-

mined to be congested at that site. The major avenues and main govern-

ment buildings in much of the commercial colonial center were often

congested. Heavy traffic and associated noise were prevalent in some

residential areas, as well, even in front of the private home of the

president of the republic.

Each of 140 streets was surveyed. The linear trend of this kind

of investigation introduces serial correlation. To control for the

regularity in the data, one-half of all data sites were randomly selec-

ted for the data analysis. The stratification allowed the number of

sites in each block to remain the same proportionally while minimizing

spatial auto-correlation (Harvey 1969, 363).

The field survey data for 40 nominal and ordinal scale variables

were stored in a computer by plotting the 140 streets on the city map,

overlaying the cell-grid system of hectares, and determining the loca-

tion of each site. Since the field data were collected and recorded

geographically, each site could be located on the city street network

between intersecting streets, in sequence, according to the order of

data collection. The surveyed sites could be readily assigned the

longitude and latitude of the grid overlay. However, where streets were

oblique to the grid, it was necessary to interpolate the location. The

location designation became the grid coordinates that were closest to

more than one-half of the sites lying between the recorded intersections.

The result was that all field sites were relegated to a total of 757 hec-

tares of land within the grid overlay. A simple algorithm was employed

to add another variable of distance from the cell center to an arbitrary

city focus at the Parque Independencia, where much urban activity is


Residential Land Use Definition of the Field Sample

Much of the developed land was residential, but the general ab-

sence of land use controls in the city resulted in mixed uses in the

field survey sites. A residential land use category would not be

obvious since it might range from strictly housing to only 14 percent

housing. The field investigation results required some criterion for

designating the predominant land use before progressing to the analysis

of the field results.

Limiting the residential land use designation to these field sur-

vey cells containing only homes would have been misleading since the

number of residential cells would have amounted to 333 out of the total

survey count of 757 cells. Where all the structures were residential,

44 percent of the surveyed city would be considered as residential.

Establishing a land use designation for each cell where there were

several uses present would have required determining the proportional

relationship and weighing the consequences of accepting a land use mix

that might fall somewhere within 14-99 percent (which represented the

range of the proportion of housing to other structures in a cell).

As the field survey data identified the number of structures by activ-

ity, it was possible to compute the percentage of total structures in

the hectare which were residential. There is no "correct" mixture

of land uses to guide one in assigning to each cell of the grid a par-

ticular land use category. The problem was to arrive at the most

reasonable proportion of residential use to other uses.

The proportion of residential to nonresidential structures in any

cell was determined by the following equations:

RES = Single Family + Multiple Family +

Apartment + Improvished Housing

RES% = (RES / (RES + INT + COM + IND)) (100)

The number of residential structures (RES) was the total of all housing

in a hectare cell. The percentage of residential land use within the

hectare (RES%) was calculated by dividing the total number of residen-

tial structures by all structures, including public (INT) and commercial

(COM) and industrial (IND) structures also found in the cell. The per-

centage conversion was obtained by multiplying the resulting proportion

by 100.

Therefore, once the field survey cell was determined to be devel-

oped land, the proportion of residential sites to all sites within it

was used to arrive at a land use designation. Beginning with 14 per-

cent (the smallest proportion of residential to nonresidential struc-

tures in any hectare found to contain housing), increasing proportions

of residential to nonresidential structures were computed to determine

at what level most or all field-surveyed land would be included which

had some housing present in 1975. The field-survey cells were com-

pared with the 1974 aerial interpretation. Table 4-2 indicates the

results of the analysis. At a criterion of 25 percent residential,

658 hectares (or 87 percent) with some housing were in agreement.


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This assumes that housing growth over the nearly one year that elapsed

between the aerial coverage and the field sampling included the develop-

ment of open land for housing purposes. Such an assumption is not

unreasonable because of the rapid appearance of marginal housing. Just

one such settlement, Buenos Aires in the western extreme of the city,

is at least twice as large as the surveyed area of 658 hectares and

much of its growth occurred after 1968.

The 138 hectares which changed from nonresidential to residential

over the year amount to less than 2 percent of the urban area. If resi-

dential land area expanded at a rate to accommodate the exisitng

density, developed land area would have had to increase 5.94 square

kilometers over the year. But it is known that marginal settlements

absorb large numbers of newly arrived inhabitants. Furthermore, land

that may be designated other than residential can include large numbers

of residences. Thus, one hectare of land containing tens of small

shacks sheltering hundreds of people, crowded against a concrete wall

surrounding a huge mill, will be designated as industrial on the basis

of area.

Another 58 hectares were designated as residential in the field

sample but were interpreted as nonresidential. Undoubtedly, some of

these cells included instances of land clearance for other development

over the year that elapsed between the aerial reconnaissance and the

field survey. There is the presumption that interpretation error

occurred, that structures which appeared to be residential were not so

when examined in the field survey.

Land conversion was infrequent. The city population doubled in

each of the post-World War II decades, a rate exceeding 6 percent since

1950 (Durand and Paldez 1965, 179; World Bank 1972, 185). There is

little vertical construction. The city area expanded at a continuous

annual rate of 6.5 percent over the 1948-1975 period. The built-up

area increased over 400 percent, from 17.09 square kilometers (10.62

square miles) to 91.45 square kilometers (56.82 square miles). Much

of this expansion occurred during the rapid economic growth period that

followed the end of the 1965 civil war.

The 58 hectares were grouped into 15 hectares of industrial use,

8 hectares of commercial use, and 35 hectares of open space. Over 60

percent of the area in disagreement was undeveloped at the time of the

field survey. The proportion of open space to other land uses as

determined in the aerial interpretation is about the same, suggesting

a consistent error in the interpretation.

The largest group of cells in disagreement, open space versus

residential, was analyzed. Most of the interpretation errors were

among cells that had middle- and high-income residential use. Thus,

the higher the income level of the occupants, the more often the field

survey indicated that the land was undeveloped. This raised the

question of whether interpretation errors were due to the low density

of the higher income, residential land use which made distinguishing

between the two uses more difficult. Mapping all 58 cells did not

reveal patterns that would suggest another explanation for the dis-

agreement between the two data sources.

Another 187 hectares of land were interpreted as residential and

found to have varying degrees of nonresidential use interspersed with

housing. The analysis of these cells indicated that over 80 percent of

the nonresidential use was commercial, followed by 16 percent institu-

tional, and 2 percent industrial. Experience in the field indicated

that where the land use mix was often residential, commercial use was

usually corner convenience stores.

Based upon the comparison of the two data bases, Table 4-2 indi-

cates that 520 hectares had some housing and were designated as resi-

dential as a result of the aerial photography interpretation. There-

fore, over 90 percent of the land common to the two data sources was

in agreement as to land use. In 333 hectares, there was no other use

indicated other than residential.

A comparison of the aerial photography and field data was made in

order to ascertain the degree of confidence that could be placed upon

the residential classification. Because the sample size is quite

large, the central limit theorem applies where the distribution of the

sample means approaches normality. The text of proportions can be seen

as a special instance of such means, involving a simple, dichotomized,

nominal-scale sample. By assigning a value of one to residential cells,

and zero to nonresidential cells, the scores can be treated as an

interval scale not requiring the determination of the exact difference

between the degree of residential versus nonresidential treatment.

Because all cells are concentrated into a bimodal distribution, normal-

ity is not present; however, with the large sample size, the distribu-

tion of sample means will be approximately normal. The mean of this

population of values of one or zero is their sum divided by the total

number of cells. The number of residential cells is the total number

of cells multiplied by the proportion that are residential.

With the use of the 50-percent criterion for designating residen-

tial land use (where there was a land use mix of housing and other

activities within the cell), there were 739 hectares included in the

analysis. Of these, 45 percent were entirely residential in both data

sources; 179 hectares were interpreted as residential in the aerial

photography but found to have a mixture of uses in the field survey.

Fifty-eight cells were nonresidential in the field survey but residen-

tial in the interpretation. Another 130 cells were just the opposite,

i.e. nonresidential in the photography and residential in the field

survey. Thus, out of the total sample size of 739 cells, 333 plus 179,

or 512 cells, could be classified as residential in both data bases.

The initial hypothesis, that no significant differences existed between

the population proportion of residential cells and the sample propor-

tion of residential land use, was tested.

The test was the single sample of proportion. The test statistic,

the Z score, is computed from the formula

Z = (ps-q u / vPuqTu/

where the proportion of residential hectares in the aerial interpreta-

tion is pu, the remaining proportion of cells is qu, and the proportion

of area in housing in the field survey is p s

The Z score for the proportion of residential cells that were in

agreement in both data sources and were entirely residential was not

significant at the .01 level for a critical region of a one-tailed test.

The initial hypothesis that there were no significant differences of

proportion was not rejected. The possibility that other percentages

of housing to nonresidential structures in a hectare were significant

remained to be tested.

Beginning with 95 percent and decreasing at 5-percent intervals,

the other proportions were tested. At the 85-percent level, the test

was significant; the difference of proportions between the sample sur-

vey and the aerial photography was great enough to conclude that it

was probable that land found to be residential in 1974 would not be com-

pletely residential in the next year.

Most land use studies of Anglo-American cities have concluded that

residential land use is approximately one-half of the total developed

urban space. Where suburbanization has been a long-term occurrence,

land use sorting will have reduced housing in the center city which is

replaced by nonresidential uses. The suburban cities, on the other hand,

contain higher proportions of residential land use.

In Santo Domingo where land use controls are weak or nonexistent,

the proportion of residential to nonresidential use should be lower.

A wide dispersal of housing in heterogeneous communities is more likely,

and unless the suburbanization process has been a significant influence,

there should be few exclusively residential areas.

The 50-percent criterion included 87 percent of field survey cells.

Most of the sample is included in the analysis: 739 of the 757 sur-

veyed cells. Choosing a lower proportion would have expanded the number

of residential cells only slightly while including those that would

obviously be better classified as commercial, industrial, or another

nonresidential use. At a higher proportion, too many cells would be

excluded from consideration in the analysis.

The 50-percent criterion for the minimum proportion of housing

to nonresidential structures in a cell became the basis for tabulating

averages. Each field variable was summed for all cells, and an average,

median, and range of values were calculated based upon the sample size

of 739 hectares.

Both the concentric zone and sector models of urban change empha-

size residential land use. In order to test the probability that one

configuration was more applicable to Santo Domingo's growth, it was nec-

essary first to delimit probable zones and sectors of homogeneous resi-

dential land use. This required an examination of the 1948 and 1974

land uses and transportation networks to determine the areas of greatest

discontinuity of activities where zone and sector limits would be



Allocating Zone and Sector Location

If the city experienced succeeding waves of growth radiating out-

ward from a central business district, then Santo Domingo's housing

would exhibit some aggregation into zones in which the within-zone

variation in housing type would be less than that between zones. The

Park-Burgess concentric zone model suggests a socioeconomic gradient of

housing with the poor located near the CBD and in a transition zone

containing tenements and other low-income rentals. Farther from the

center of the city are middle-income homes which are superceded by high-

income residences as the distance from the central business district

increases. Santo Domingo's residential land use does not resemble the

ideal model, however, since it is sited at the Caribbean coast which

has prevented the complete evolution of a circular pattern.

The land use data analysis confirmed the clustering of both low-

and high-income housing and dispersal of medium-income housing. There-

fore, utilizing an average distance for each type of housing would not

delimit the probable zones. A comparison of land use over the 28-

year period, shown in Figure 5-1, revealed that the least change in

land use was concentrated at approximately 1,000 and 2,500 meters from

the city center established at the Parque Independencia. Concentric

zone theory would argue that the boundary areas between zones would


1 20


1000 2000 3000 4000 5000 6000


(in meters)

Figure 5-1: Frequency in Hectares, of Stable Land Use, 1948-
1975, by Distance from the City Center

experience greatest instability. For Santo Domingo, then, the zonal

boundaries would be indicated between the stable modes. The inner

limit of the first zone was established at 1,000 meters, and it was

assumed that low-cost housing lay beyond a radius of 1,750 meters from

the CBD, or one-half of the distance between this and the other stable


As Table 5-1 shows, 542 meters separated the average distances

for medium- and high-income housing. One-half of the distance, 271

meters, was added to the average distance of high-income housing, 4,741

meters from the city center, and this distance of 5,022 meters was desig-

nated the boundary between high- and medium-income residential land use.

The boundary between low- and high-cost housing was one-half the dis-

tance from this to the inner limit of low-income housing. All that

remained was to establish a maximum extent of the outward reach of resi-

dential land use. Since the open land averaged 7,000 meters distant

from the CBD, medium-cost housing was extended approximately 1,700 meters

to equal the distance arrived at between the boundaries of low and

medium income.

The final zone configuration is shown in Figure 5-2. The zones,

including their ranges, are

Zone 1 Other land use, 0 to 1,674 meters;

Zone 2 Low-cost residential land use, 1,675 to 3,348 meters;

Zone 3 High-cost residential land use, 3,349 to 5,022 meters;

Zone 4 Medium-cost residential land use, 5,023 to 6,696 meters;

Zone 5 Open land use, 6,697 to 11,700 meters, at the western

extreme of the city.



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Establishing sectors was less complex. Hoyt hypothesized that

sector boundaries, influenced by topography and evidenced in the loca-

tion of major transportation-communication corridors, continue to grow

with outward expansion of the city. Growth of residential neighbor-

hoods became dependent upon the corridors for continued accessibility

to central business district activities. McElrath's (1962) study in-

corporated 10 sectors which were found to be too many. Johnston (1971,

334) concluded that linear gradient change as evidenced in within-zone

heterogeneity was best controlled utilizing only a few sectors.

Both the land use and the city maps, as well as the field experi-

ence, suggested that six sectors would be needed to differentiate land

use sufficiently to test the applicability of the sector model. These

six, bounded by the coastline, the river, the limestone terraces, and

the major avenues, are as follows (Figure 5-2):

Sector 1 Caribbean Sea and Avenue J. Contreras;

Sector 2 Avenue J. Contreras and Avenue S. Bolivar;

Sector 3 Avenue S. Bolivar and Avenue S. Martin;

Sector 4 Avenue S. Martin and Avenue J. Duarte;

Sector 5 Avenue J. Duarte and the Ozama River;

Sector 6 Ozama River and the Caribbean Sea.

The least elevational change is found in Sector 1. The second sector

rises from 10 to 25 meters, while Sector 3 has the highest elevation

found along the limestone terraces extending east to west parallel to

the sea. The remaining sectors, 4, 5, and 6, range from 50 meters to

sea level and include steeply sloping land in the deep arroyos in the

northwest corner of the city, along the riverbanks,and at the seacoast.

The two model configurations were superimposed on the 1948 and 1974

land use maps. Every hectare was assigned both a zone and sector designa-

tion; thus, any cell of land as determined in the 1974 land use mapping

was given a location in the grid, and all other cell characteristics were

associated by this location variable. Many of the land use cells com-

prised the five zones which crossed all the sector boundaries. Most of

the sectors contained portions of all five zones.

Testing the Models of Land Use Change

In the assessment of the zone and sector models, the residential

land use determined by aerial interpretation represented the population

of all such land use in the two base years. The field survey of 10 per-

cent of all land use in the city included 739 of the 9,145 hectares of

urban land. A merge by cell of two data bases resulted in the selec-

tion of 512 hectares established as residential in the 1974 aerial photog-

raphy and having at least 50-percent residential in the field survey.

The allocation of every hectare in the city to one of five concentric

zones and six sectors meant that each hectare of urban land could be

given scores for its location in both a zone and sector.

Total residential land use in the 1975 field survey data base was

sufficiently large, at 512 hectares, to be tested as representative of the

entire city. The 512 hectares were 12 percent of the 1974 residential

land area. The field survey information was grouped into low-, medium-,

and high-income land use as established by the aerial interpretation,

and the frequencies were recorded in a matrix of land use type (Table

5-2). The zones were the rows and the sectors were the column figures

in the initial 5 x 6 matrices for each of the three residential land use


Table 5-2: Frequency Matrix of Field Survey, 50-Percent Criterion, for
Zone and Section Models, by Residential Land Use Type


Zones 1 2 3 4 5 6 Totals

1 3 0 0 2 5 7 17

2 0 0 0 26 18 29 73
Low-Income 3 0 0 1 19 43 38 101
4 0 4 3 0 0 6 13

5 4 0 19 0 0 0 23

Totals 7 4 23 47 66 80 227

1 10 0 0 1 0 0 11

2 5 2 4 3 14 12 40
Medium-Income 3 4 0 5 8 5 21 43
4 12 3 4 0 0 5 24

5 7 40 33 0 0 0 80

Totals 38 45 46 12 19 38 198

1 12 9 7 5 0 0 33

2 9 3 5 0 0 0 17
High-Income 3 0 2 11 0 0 0 13
4 1 2 4 2 0 0 9

5 5 6 1 2 0 0 14

Totals 27 22 28 9 0 0 86

The chi-square test is a general procedure that can be used to

evaluate whether these frequencies of grouped, empirically collected

data differ significantly from expected frequencies. Several assump-

tions were involved. These included random sampling, independent selec-

tion, and equal proportions. Expected frequencies were calculated

for each contingency problem involving a land use type. The resulting

matrices are given in Table 5-3.

Since housing sites can range from very small toall-inclusive

plots within a hectare and theoretically could encompass an entire zone

or sector, any matrix cell could have a wide range of possible values.

However, since land development tends to reflect a much more limited

range, the cell frequencies are whole numbers of low value, the result

of a measurement unit that forced a single land use cell designation.

A random sorting of the field data would result in a matrix of 30 cells

in which all land would be evenly distributed. Deviation from the

expected frequencies was tested using the chi-square test of signifi-

cance. Its use required a correction for continuity in order to ensure

that the sampling distribution approximates the sampling distribution of

the chi-square table. Generally, the fewer the number of matrix cells

and more nearly equal the marginal totals, the smaller the sample size

must be, but whenever any of the expected frequencies is less than six,

it becomes necessary to make some adjustment (Blalock 1972, 285-286;

Taylor 1977, 110). In practice, such an adjustment involves combining

categories in a rational manner in order to reduce the number of matrix

cells by combining where frequencies number less than six. Rather than

exclude field data and in consideration of the influence that topography


Table 5-3: Expected Frequency Matrices for Field Data, 50-Per-
cent Criterion, for Zone and Sector Models, by
Residential Land Use

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