A project has been set up to:
provide decision makers with rapid estimates of changes in acreage for various economically important crops using high resolution satellite data;
design, develop and implement a transportable operational information system in a computerized environment for future use by other services of the Commission. High resolution satellite imagery has been used to provide rapid estimates of annual changes in areas of various important crops in Europe, and estimates of the potential yield of these crops. The system was designed to give results only at the European scale, and not to provide accurate statistics at a more local level. The project now monitors 53 sites scattered over Europe each 40 by 40 km (6% of areas used for farming in Europe). The agricultural information must be delivered rapidly in order to be of use, a target of 10 days has been set. This requires a novel and industrial approach to the image analysis and the project has therefore developed automatic geometric and radiometric correction of the incoming data, computer aided image interpretation without access to up to date ground data, a knowledge oriented data base, automatic classification using a merge and split algorithm, multitemporal cross classification, and validation of the interpretation once a year, using ground data collected specifically for this purpose. Each site includes anything up to 10 000 fields. It would be an enormous task to examine each field individually. Instead, within each site the interpreters analyse in detail about 16 areas, known as segments, of just under 50 ha each. These same segments are used by ground teams to collect information on the crops growing in each field in every segment. The data collected by the field teams are used to check the work of the interpreters at the end of the year. Overall results seem to confirm the operational character of this technique to acquire agricultural statistics.