Mapa pokrycia terenu w Polsce w skali 1:1 000 000 jako wynik wizualizacji bazy danych CLC-2000

W artykule przedstawiono problematykę kartowania użytkowania ziemi i pokrycia terenu, realizowaną w ramach różnych przedsięwzięć międzynarodowych. Omówiono program Unii Europejskiej CORINE Land Cover (CLC) oraz wyniki jego realizacji w Polsce w ramach projektów CLC-90 oraz CLC-2000. Porównano zawartość baz danych "pokrycie terenu" opracowanych w trakcie realizacji obu projektów, wykazując zmiany, jakie zaszły w użytkowaniu ziemi w Polsce w ostatniej dekadzie XX wieku.

At the moment there are many international programs which collect data on land cover and land use. Some of them have to be mentioned: Global Terrestrial Observing System (GTOS), International Geosphere-Biosphere Programme (IGBP), Pan-European Land Use and Land Cover Monitoring (RELCOM) and EU's CORINE Land Cover (CLC). In the early 1990s a database of land cover in Europe was created within CLC program. It provides information on the distribution of 44 main land cover forms. The database is to be updated every 10 years, so in the beginning of the 21st. century a first update was conducted. It resulted in a CLC-2000 database and a base of land cover changes in the years 1990-2000. Landsat satellite images taken on the turn of the 20th. century were the source material used in the process. In 2002 Poland joined the land cover update project. Instytut Geodezji i Kartografii (Institute of Geodesy and Cartography) took up the task. The criteria for the elaboration of the new database (CLC-2000) remained the same as for the previous one (CLC-90), however the method had been changed: it employed visual interpretation of images displayed on a monitor screen. The methodology assumed geometric correction of the database from the nineties. The aim was to unify the base on European level and make it consistent. Therefore it focused on proper identification of particular land cover forms (in accord with the modified legend), accuracy of their borders and formal agreement of topology and data format. Correction of CLC-90 database was performed on the basis of satellite images from the nineties transformed into ,,1992" projection. New satellite images were also transformed to the same projection. Following the database update methodology, the new base registered only the changes over 5 ha (for changes of existing Forms area) or over 25 ha (when a new cover form appeared). A comparison of land cover databases for 1990 (CLC-90) and 2000 (CLC-2000) revealed land cover changes in the last decade of the twentieth century. In most cases they turned out to be minor. They covered just over 2500 km2, which represents only about 0,80% of the area of Poland. There are also several other products which are going to be prepared within CORINE Land Cover program. They include satellite ortophotomaps, mosaics of satellite images covering particular countries and the whole Europe, as well as raster and vector databases of land cover in different spatial resolutions. Institute of Geodesy and Cartography also prepared a map showing the distribution of all 31 land coverforms in Poland, which were stored in CLC-2000 database. The map was published at a scale of 1:1 000 000.