past. Most important, perhaps. it can be used to predict what 
will happen or has happened in another location or another 
point in the past. 
3. RESEARCH METHODOLOGY 
This section presents a summary of the materials that 
were used and of the methodology. Details of these can be 
found in the Ph.D. thesis of Costa (1996). 
3.1 Study Area 
The Metropolitan Region of Belo Horizonte is located 
in the Center-Western region of the state of Minas Gerais. 
Brazil. and is limited by the coordinates 19925" and 22913' 
South latitude to 43900" and 44919" West longitude . as 
indicated in figure 1. This region constitutes the main 
economic area of the state of Minas Gerais. and is the third 
most important metropolitan area in Brazil. 
   
  
South America 
S Legend: £3 r^ 
© Metropolitan Area of Belo Horizonte B = 
* State Capital 7 
° City (S 
District limit E... 
Figure 1 - The study area 
The study area of this research corresponds to the Central Area 
or Metropolitan Area of Belo Horizonte (MABII). which has as 
an important feature its ever-increasing urbanization and the 
fact that it represents the oldest occupation and comprises the 
most important urban areas (Belo Horizonte. Contagem. Betim, 
Ribeirào das Neves. and Santa Luzia) in this region. 
Due to its complex and abrupt morphology. the MABH has 
serious environmental problems caused by the unplanned urban 
growth. 
3.2 Modelling the Physical Potential of the MABH to the 
Urban Land Use 
Diverse environmental problems associated to the urban land 
use can be frequently found in the Metropolitan Area of Belo 
Horizonte. such as: mountain creep. soil erosion, deforestation. 
water pollution. ctc. f 
Employing remote sensing and GIS, this research has 
elaborated a physical potential modelling of the MABII in order 
to define the suitability of this area to urban land use. Some 
physical aspects and the urban land use were considered in this 
process. 
The methodology that was developed followed the flow chart 
presented in the figure 2. 
  
Selection of the 
physical data 
| 
ER [ si I-1 Dri ege | 
Producing 
secondary data 
si Erosion Occupation Permitted, 
Potential considering drainage 
| ] 
x 
Defining the data 
cross rules 
i 
Physical potential 
modelling Land Use Map 
| 
, 
ENVIRONMENTAL 
EVALUATION 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Figure 2 - Methodology flow chart 
After collected the necessary physical data (slope. soil erosion. 
and drainage). these were organised in raster format to support 
manipulation and produce a modelling of the study area in a 
GIS. Generally speaking. a raster data structure is employed to 
overlay functions and is required in the elaboration of real 
world models (Burrough. 1986). 
It is important to emphasize that this research should have 
collected more information from the physical environment to 
produce a more accurate modelling. but theses data were not 
available at the time the research was effected. However. as a 
modelling. this parameter has to be considered in the final 
analysis. 
3.3.1 Producing the Elevation and the Slope Map: Four 
topographic maps of the study area were used to collect 
elevation data. The maps were divided in cells of 500 x 500 
meters (1x1 cm). and the elevation of each cell was registered. 
following the methodology established by Star and Estes 
(1990). According to these authors, one method for collecting 
the elevation in a map to produce a raster format file is to take 
into account the arithmetic mean of the points (level lines) 
found in each cell. as represented by the formula: 
Elevation ^ (Z C)/N 
where: C = value of the elevation curve. in meters; 
N = total number of elevation curve found in the cell. 
On the basis of this, it was calculated and produced a slope map 
using Arc-Info commands. The resulting data were classified 
according to the IPT (1991). Brazilian Technologic Research 
Institute. classification. the features of the area and the 
limitation of the raster format data. The classes used are: Class 
1 - « 10% - areas with no restrictions to the urban 
occupation; Class II - from 10 to 20% - areas with 
restriction to the urban occupation; Class III - > 20% - 
areas where urban occupation is prohibitive 
3.2.2 Elaborating the Soil Erosion Map: The soil map 
used in this research (scale 1:250.000) was obtained from 
Fundagào Centro Tecnológico de Minas Gerais (CETEC). The 
218 International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 
soi 
era 
Dy 
Ha 
ere 
it 
ag! 
po! 
of 
pre 
ou 
ch: 
ne 
cla 
bu 
po 
Th 
det 
the 
gel 
of 
ma 
wa 
urt 
oth 
oc 
pei 
riv 
thi 
riv 
the 
OC 
the 
res 
Ea 
the