888 
help further studies in yield forecast. 
We have the intention to orientate this program taking into 
account the priorities of the MARS (see References) project, 
approved by the European Parliament. 
3.DATA PROCESSING SYSTEM 
The data processing system is a basic tool during the development 
of remote sensing based crop information system. Its structure 
(Fig. 1) shows the present development stage. Later, the 
controller unit should become a set of expert systems each 
dedicated to one of the basic tasks. The subsystems are at 
different development stages and the whole system is also not 
integrated enough yet. 
The image analysis subsystem (IAS) has been the most important 
part up to now, being the basic tool for the agricultural land 
use map— ping studies. It provides for the major geometrical, 
registration, radiometrical, supervised/unsupervised 
classification and error assessment procedures. 
Figure 1. The scheme of the satellite data processing system 
The reference data handling subsystem (RD5) facilitates the input 
and data management of all the necessary ancillary data that are