Oliveira, Ronaldo Pereira de 
  
and industrial expansion. Land fragility evaluation has straight relationship with susceptibility to natural phenomena. A 
high fragility class implies in a high probability of severe damages or even extinction of species from the ecosystem. 
In a qualitative approach for land vulnerability assessment, it was related to erosion susceptibility of slope areas, 
drainage condition of low land areas, and climatic factors in especial precipitation. The interpretation of environmental 
vulnerability of the lands was elaborated upon analysis of updated soil profile information and new map units 
delineation. In this sense, the evaluation methodology is further detailed because its possibility of improvement by 
DTM analysis that was not considered in project phase. Which has divided the total area into highlands, due to erosion 
susceptibility, and low lands, due to drainage condition. A map was based in a two step procedure for thematic attribute 
generalisation. The first step was to establish a relationship of soil profile conditioning factors and adopted land 
vulnerability classes, as shown in tables 1 and 2. The following steps were soil class generalisation and geo-objects 
aggregation procedure of neighbour areas within the same vulnerability classification result. 
classification on low lands. 
Table 2. Guidelines for land vulnerabili 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Low (B) no no no no no none >200 - 
subcaducous 
Intermediate once each tropical forest 
(M) no no no yes no 10 years 100-200 and grassland 
meadow 
Once cach 5 sandbanks and 
High (A) yes yes no yes no 50-100 halophyte 
years 
meadow 
; sandbanks and 
Very High 
yes yes yes no yes once a year <50 halophyte 
(MA) meadow 
Extremely : Sandbanks and 
High (EA) no yes no no yes frequently | superficial mangrove 
  
  
  
! - Considered as reflection of soil hydrologic conditions. 
2.14 Land Environmental Quality: 
This was the project last product, generated 
from the relationship of land vulnerability 
and land cover for planning purposes. The 
abstracted integration of these thematic 
information were expressed into a two 
dimensional table (Embrapa, 1999a), giving 
an evaluation output class to each unique 
combination of both input domains. 
Following the same basic criteria defined 
for vulnerability evaluation, the total area 
was divided into two great geomorphologic 
domains, as erosional landforms of 
highlands and sedimentation basis of low 
lands having distinct considerations. After 
that, it was possible to perform the 
topological overlay of both geometric 
representations. Once more, the digital soil 
map topology (Figure 2) was a basic source 
of delineation of land environmental quality 
information by means of both GIS spatial 
analysis and its database linkage to 
SIGSOLOS (Embrapa, 1997). 
  
iiid 
Figure 2. Overview of the digital soil map topology. 
  
  
1076 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.