THE EFFECTS OF IMAGE SCALE ON DELINEATION OF ERODED LANDS USING REMOTE-SENSING DATA

With the development in sensor technology, in recent years, spaceborne multi-spectral data with improved spectral, radiometric spatial and t emporal resolution are now available to the user community. Higher spa tial resolution provides more details about the Earth's surface featur es, compared to medium or coarse spatial resolution data by virtue of smaller instantaneous field-of-view (IFOV) at a given wavelength. This study aims at bringing out the additional information on soil erosion that may accrue from the interpretation of large scale i.e., 1.50 000 Landsat Thematic Mapper (TM) analogue data over what could be derived from 1:250 000 scale. Owing to improved discernibility of eroded land s at larger scale the pockets of eroded lands as small as 2.25 ha coul d be mapped at 1:50 000 scale as compared to 56.25 ha that is possible from 1:250 000 scale data. Besides, substantial refinement in the del ineated boundaries of these lands have also been observed. The approac h and results are discussed in detail.