ANALYSIS OF LAND USE CHANGES IN THE TRI-CITY METROPOLITAN AREA BASED ON THE MULTI-TEMPORAL CLASSIFICATION OF LANDSAT AND RAPIDEYE IMAGERY

The aim of the study was to diagnose the main trends of land cover changes around urban agglomerations over the last twenty years (1997–2016) on the example of Tri-City, and to present them statistically and graphically in the form of compilation of numerical maps. The research was performed on the basis of remotely sensed data: LANDSAT 5 TM satellite imagery from 1997 and RapidEye from two records (2011, 2016). The metropolises of Gdańsk, Gdynia and Sopot, constituting the core of metropolitan area (MA), and municipalities belonging to the Tri-City MA located in its vicinity were selected for detailed analyses – the inner zone of 2 communes and the outer zone, also of 2 communes (MA outskirts). In the selected metropolitan area, communes with good and poor natural conditions for agricultural production were studied. The analyses were performed on processed images (colour compositions), which were subjected to supervised classification with the maximum likelihood technique. The quality control of supervised classification showed an accuracy of 87.2% for LANDSAT 5 TM scene analyses and 93.8% for RapidEye imagery. The Kappa coefficient for the discussed classification was, respectively: 0.85 (LANDSATTM) and 0.93 (RapidEye). The conducted analyses showed that in the communes there were changes in the way of using arable land and grassland. The greatest changes took place in communes with a low Agricultural Production Space Valuation Ratio (APSVR). Grassland, and to a lesser extent areas with scattered development, replaced arable land. In Gdańsk, Sopot and Gdynia, belonging to the TriCity, the greatest changes over 20 years took place in arable land, which altogether diminished by 17%, and forest land (13% in total). All this to the benefit of grassland (increase by 23%) and built-up areas (10% in total in all cities).