tivities 
1 of the 
| to the 
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re area 
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Consequently, the ecological balance has been compromised by 
the sedentarisation, the acquiring of a great number of livestock 
for commercial motives, the demographic growth, the 
modernisation of transport means and, finally the overpasture. 
Hence, we propose to develop and to give the contribution of 
the GIS tool analysing and integrating the significant 
parameters for the steppic area management by considering 
area's physical capacities and the aspiration of populations 
living on it. 
IL METHODS 
e Pasture territory cartography in terms of grazing and land 
cover from satellite images (Thematic Mapper (see Fig. 1). 
This step requires a geometric correction of the image with 
regard to the topographic map. 
* Digitalisation of the different layers ie.: administrative 
limits of the region, level curves, roads network and 
agglomerations, hydrographic network, and the localisation of 
the pastoral wells and the drillings. All these layers were 
reported to the scale of 1/ 100000. 
The digital terrain model and the slope map have been 
determined, by interpolation, from the level curves layer. These 
digitised data stocked with the format of ATLAS*GIS software 
then were transformed and exported on different standard 
formats to be used by MAPINFO and IDRISI softwares. 
In the second step, which concerns the socio-economic data, an 
investigation next to the breeder and the local authorities was 
undertaken in order to get: 
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- a questionnaire (township) regarding all information about the 
township i.e.: population number, population distribution by 
sex, breeder number, livestock number, fashion of living, etc. 
- a questionnaire (breeder) is established. It contains the 
breeders’ names living in the townships and acquiring livestock. 
This questionnaire informs us on breeders, their age, their 
livestock (nature, density.), pasture area, etc. 
These data serve for the development of a data base of the GIS 
type. To this effect, we require a modelisation of the physical 
and socio-economic data using the following steps: 
- data analysis and inventory ; 
- data conceptual model and dictionary; 
- data logical model; 
- and the data physical model. 
This data base is used at several levels: 
A. Ina given plan 
- Estimation of the pasture rates and densities over the total 
surface of the study area by computing the total number of 
livestock over the total surface of grazing (see Fig. 1). 
- Evaluation of the charge index of each township by computing 
the total number of livestock over the total surface of grazing 
(see Table 1). 
    
   
   
       
      
    
  
    
ARS 
E ER 
9 227) RS 
7 287180 
f Kr 
A ERE 
OO OQ oen gf fd loses 
EN ZA : 
Kx BIE % A Beidha 
e 2 j QOO! RIS d 
ASSIS 
AMA 2 to 
EX 
e 
+ 
ARS 77 
SAX 7 
oS 
c A 
3 a 
ONS 
ve x 
  
0 86 172 
Scale: | Ld 
Km 
    
    
es 
X ) 
Ox j 
XH 
SU 
PRANKS 
RAL 
Ve > 
p (XR 
SIRF 
ete 
SKF 
   
  
3 26000 animals 
  
Q 2600 animals 
[OX] Good state grazing 
ZZ Degraded grazing 
Very degraded grazing 
[71 Culture 
Townships administrative 
limits 
  
  
  
Fig. 1. Synthesis map of information layers overlaying (Livestock density, land cover, administrative limits). 
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998 747