According to Fig. 2, the GIS will have to be applied 
to the data base for the whole Patagonian territory. 
Thus we proceed from the ,experimental stage“ to 
the ,operational stage“. During the initial phase, 
activities concentrate on data acquisition, first in test 
areas, then for the whole area under consideration. 
Establishing the desertification model and processing 
the complete data base gives a level of information 
which allows to draw conclusions about activities in 
the real environment. 
Knowing the extent of desertified and endangered 
areas, finally provides the necessary detailed 
information to formulate appropriate desertification 
control measures. 
4 International Cooperation: 
Project ,Desertification 
Control in Patagonia“ 
Under the name of ,Desertification Control in 
Patagonia^ (Lucha contra la desertificación en la 
Patagonia), a Project of Technical Cooperation 
between Argentina and Germany was defined in 
1987. The official support was given by the 
respective Ministeries whereas the realization was 
trusted to INTA (Instituto Nacional de Tecnologia 
Agropecuaria) and GTZ (Deutsche Gesellschaft für 
Technische Zusammenarbeit). Since the operation 
was to be carried out in Patagonia, the headquarters 
were installed with the regional INTA-group in San 
Carlos de Bariloche (Province of Rio Negro). Head of 
the German Counterparts is Dr. J. Goergen. 
The project started in 1990 will run for at least 4 
years. The regional INTA group provides an excellent 
base of knowledge and data for desertification 
research. On the other hand, data acquisition by 
Remote Sensing as well as GIS technology is 
introduced by the German counterparts. Because 
of the large range of necessary activities, experts 
from different fields are contracted when required. 
Technical backstopping is provided by the IPF 
(Institut für Photogrammetrie und Fernerkundung, 
University of Karlsruhe). 
The final goal of the Project means ,control“, i. e. 
improvement of the present situation. Consequently, 
High-tech features like Remote Sensing and GIS 
technology must be regarded as efficient tools - no 
more but no less. 
5 Technical Procedure for 
Data Acquisition 
The initial stage of the Project is characteristic for 
difficulties which are common to many environmental 
152 
problems, particularly in remote areas. Among these 
the lack of updated topographic base maps is typical. 
Though there fortunately exist in Patagonia topo- 
graphic maps in Gauss-Krüger-coordinates, which 
provide the geodetic reference, their content and 
status do not allow any environmental monitoring. 
Nevertheless we should point out that those 
topographic maps contain height information which is 
important for most environmental projects. The map 
scale for Patagonia is not consistent: it varies from 
1:100 000 to 1:250 000. However every area is covered 
by a map, no matter in what scale. INTA and other 
agencies have already done a lot in land degradation 
surveys, soil and vegetation mapping, etc. 
But some areas are only sporadically well covered, 
like Maquinchao (see paragraph 6). A homogeneous, 
complete, informative data base is only provided 
by satellite imagery. Airborne photography does not 
seem to be an adequate tool for environmental 
monitoring of Patagonia as a whole: the area involved 
is too large; the spectral resolution is poor, even for 
colour IR-imagery; and finally, data processing should 
be performed in the digital domain, because of the 
necessary analysis by GIS. 
800 000 sqkm represent a ,very large area^ when 
monitoring land degradation even for satellite 
imagery. Therefore a hierarchical system has been 
established: 
Patagonia (the whole region) - NOAA data 
4 Transects - LANDSAT MSS 
Representative areas - LANDSAT TM, 
Special imagery and field check. 
The satellite imagery used does not require further 
comments (BAHR, 1991). A novelty lies in the 
procedure for mapping the area by the hierarchical 
approach. Transects (Fig. 3) carefully defined by 
Geo-ecological experts cross areas where specific 
information has already been mapped. 
Each transect is covered by 3 to 5 LANDSAT scenes. 
While Patagonia as a whole would require approx. 
50 scenes, only 15 are needed for these transects. 
Coupled with the available ground data, detailed 
analysis will reveal the desertification processes 
taking into account the specific types of phenomena 
involved which vary considerably from one transect 
to the other. 
Beside the transects, it is necessary to go into further 
detail - since even the individual plant serves as an 
indicator for desertification! Consequently field check 
and large-scale mapping is also required. This is done 
in ,representative areas“ of particular interest (e. 
g. Maquinchao - see paragraph 6). Here all useful 
data are compiled by means of field work or Remote 
Sensing Techniques. On the other hand, the capability