Drainage network analysis of LANDSAT images of the Olympus-Pieria mountain area, northern Greece

Abstract

Abstract This report is an account of findings derived from a visual examination of 1:250000 paper print enlargements of LANDSAT black-and-white images (from bands 5 and 7), paper print enlargements of LANDSAT false-colour composites (bands 4, 5 and 7) and maps of a representative part of the Mediterranean climate area of the Olympus-Pieria mountains and the surrounding area in northern Greece. The main finding derived from this image and map interpretation was that the l:250000-scale enlarged prints are far more suitable for quantitative analysis of drainage networks than the topographical maps of an equivalent scale. For the study area as a whole, the LANDSAT images showed channels (streams) up to higher order than the same scale topographical maps. Also, the number of streams and the total stream lengths of each order, which appeared on LANDSAT images, were significantly more than on topographical maps, illustrating the greater amount of detail which can be extracted from images. Furthermore, it was concluded that near-infrared (band 7) LANDSAT images offer the best prospects between the four MSS spectral bands of LANDSAT-3 for the detection of drainage lines in vegetated and fluvially dissected areas but they are less effective in the detection of small drainage lines, particularly where they are turbid or choked with vegetation; however they are still superior to the red (band 5) image. This limitation was partly overcome by using false-colour composites since they were more suitable for the recognition of the vegetated streams.