A STUDY OF METROPOLITAN AREAS IN BRAZIL: A MODELLING USING GIS
AND REMOTE SENSING TECHNOLOGIES
Sandra Maria Fonseca da Costa
l
Jorge Pimentel Cintra?
University of Vale do Paraiba - UNIVAP
7 University of Sào Paulo - USP
Address: Rua Sorocaba, no 45/Ap 24 - Jdim Alvorada - SJCampos - SP - CEP 12240-6000
E-mail: sandra«?univap.br
KEY WORDS: remote sensing. geoprocessing. urban
planning. modelling.
ABSTRACT
The process of metropolisation. verified in Brazil. was more
intensive during the period. of 1950 to 1975. It was quite
difficult to plan and monitor this process in Brazil. as well as
develop methodologies to study and control this situation. Even
now we continue without essential information about the
metropolisation process. Considering this. the principal subject
of this work was creating a methodology to study metropolitan
areas. to help Brazilian planners understand the urban
environment and to solve the problems rapidly and precisely.
This research was directly mainly to identifving the urban
expansion process of the Belo Horizonte Metropolitan Area
(BHMA). located in the state of Minas Gerais. between 1950
and 1990. evaluating the urban land use. and the suitability of
the environment to these urban land uses whilst having regard
to the principal environmental effects caused by this process.
The methodology used in this research has been very useful to
monitor the urban process as verified in the BIIMA and the
results obtained has provided georeferenced thematic
information and a data base. which can be update
systematically. through the integration of remote sensing and
GIS.
I. INTRODUCTION
The growth of metropolitan arcas in Brazil was a result of a
rapid process of industrialisation. as also of the increase of
urban population. In 1940. 32.4 percent (12.9 millions) of the
population lived in urban arcas and 68.7 percent (28.3 millions)
lived in rural areas. This rate had changed by 1991: considering
the total number of inhabitants. 75 percent (112.8 millions) was
urban and 25 percent (37.6 millions) was rural.
These data show that Brazil is now an urban country. but its
population is concentrated in some spatial points. above all the
largest cities.
The concentration of inhabitants in some cities. associated to
the deficient urban planning. has given origin to many
problems. one of the most important being the fact that the
share. of the population which does not have access to
information come to live in prohlematical areas which. despite
being attractive in view of the low price of real state. are
problematical as regards to their physical characteristics. As a
result of this. the environment has been damaged during these
years. affecting the quality of life.
The technology of Geographical Information Systems and that
of Remote Sensing have been joined to detect and. control this
process in a way which is easier and faster than the traditional
methods of surveying.
In this context, this research has made use of these two
technologies to develop a methodology to evaluate the
suitability of the environment of the Metropolitan Area of Belo
Horizonte. state of Minas Gerais, Brazil. to help the work of
planning bureau. This methodology considers urban land use.
paying special attention to its main environmental effects.
2. REMOTE SENSING AND GIS: AN OVERVIEW
The geographic space is the result of the integration of man in
his environment. According to Souza (1988). this space is
materialised in different aspects (an urban landscape. a business
centre. the urban fringe etc). being the combination of natural
and social elements. and a result of the historic process. Souza
also mentions that, from this standpoint. the landscape is
dynamic because society is dynamic. Each time society is
transformed. there is a consequence on the landscape.
Orbital remote sensing has been used as an important
technology to help various urban researches. and to support
research analysis of this spatial dynamics. A difficult point in
using remote sensing technology for urban studies is the
diversity of features found in the environment. Forster (1985)
attests that an urban area is composed by different targets like
concrete. asphalt (streets and avenues). roofs of different
materials. exposed soil. grass. trees. water. etc. Some of these
materials are smaller than a pixel resolution.
Since the urban environment is very complex. the remote
sensors that have a better spatial resolution (as TM/LANDSAT
and HRV and PAN/SPOT) are more qualified to urban studies.
since they area able to produce a more detailed identification of
the terrain.
Another technology that can be very useful to urban planners is
the Geographical Information System (GIS). Burrough (1986)
defines GIS as a particular form of information system applied
to geographical data. According to him. it is "a powerful set of
tools for collecting. storing. retrieving at will. transforming and
displaying spatial data from the real world for a particular set of
purposes.”
Extending this definition. Aranoff (1989) points out that a GIS
data base is associated to a real world model. which can be used
to reproduce some aspects of reality to help the planning
process. Models are designed to mimic only selected aspects of
reality. In general. the more factors a model takes into account.
the more complex it becomes and the more expensive it is to
use and maintain it. A more complex model may or may not
provide "better" answers: it depends on the questions to be
addressed (Aranoff. 1989).
Aranoff (1989) also reports that a model is used to answer
questions about what exists now or existed at some point in the
