Figure 4 . changes image ( 1986 - 1995) 
vegetation indices ( 1986= green: 1995= red) 
  
  
nd 
nes of 
anges 
nes of 
non 
hange 
  
  
end 
ones of 
hanges 
ones of 
non 
hange 
  
(images TM du 08.04.95 £ du 17.05.86) 
7. CONCLUSION 
The conception and the development of a data base able to 
resolve the problems of management and planification. of the 
renewable resources involve a cumbersome conceptual and 
methodological work. This work must be done without regard to 
the technological tool to be used. 
The satellite and remote sensing data become dominant and 
efficient in the management of the renewable resources. Their 
implementation in a data base mean that manv crustal problems 
were resolved such as raster images and storing capacity. 
However, the advantage is that the data are numerical data so 
that it is easy to manipulate them by a computer. 
  
—— d 
zones of 
Changes 
  
zones of 
non 
Y change 
  
  
In this studv the objectives were reached : 
e a land cover map was obtained after treatment done on TM 
images. 
e a cartographic map of the steppic evolution and changes was 
produced. 
The TM Landsat multispectral images were used and treated to 
find out the land cover map. The multidate images (MSS an TM) 
were processed to undertake a multitemporal study. This was 
based on two methods of changes detection leading to a 
cartographic map of evolution of the renewable zones. 
These maps show the kind of changes happened on a period 
known beforehand. 
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 683