Integrated use of Landsat TM and SPOT panchromatic imagery for landslide mapping: case histories from southeast Spain

Abstract

AbstractThis paper demonstrates some of the ways in which digital space imagery can be used for landslide mapping. Landslides ranging in size from a few metres to several hundred metres across have been studied at a test site in semi-arid terrain in Almeria Province, SE Spain. The study illustrates the capabilities and limitations imposed by spatial and spectral resolution in Landsat Thematic Mapper (TM) and SPOT panchromatic space imagery. The results demonstrate the scales at which, landsliding which can be studied, using SPOT P and Landsat TM imagery.Spectral and textural features of landslides were enhanced digitally. Textural discrimination was improved by linear contrast stretching combined with edge enhancement by adding back the results of Laplacian filtering. Spectral features of landslides, including soil moisture dependent vegetation and rock debris types, are well-displayed in supervised RGB colour composites and band ratio images.A data integration technique, the Brovey Transformation, was used to produce colour composites combining textural and spectral features from SPOT Pan and Landsat TM imagery. Landslides with a minimum width of 250 metres can be identified in space images. Interpretation of results revealed the presence of several previously unrecorded landslides.Daedalus 1268, Airborne Thematic Mapper (ATM) digital imagery has been used to demonstrate the value of improved spatial and spectral resolution imagery for landslide mapping on the scale of the Spanish test sites. The results illustrate the future system requirements for more detailed landslide mapping and demonstrate the improvements of scale which will occur when space imagery with pixel sizes of five metres becomes more readily available.