A study of landslide hazard in S. E. Spain using integrated DEM, orthophotography and Landsat ETM imagery
J. McM. Moore, A. M. Davis and P. J. Mason Remote Sensing Unit, T.H. Huxley School of Environment, Earth Science and Engineering, Royal School of Mines, Imperial College, South Kensington, London SW7 2BP, UK This paper demonstrates how integration of digital elevation models (DEMs) with enhanced Landsat ETM imagery for landslide identification and geohazard mapping in semi-arid terrain in SE Spain. Digital elevation models were generated using stereoscopic aerial photographs at 1:18000 scale. The aerial photographs were ortho-rectified using the DEMs and then used to geo-rectify the Landsat ETM imagery into a consistent datum and projection. Spectral enhancements of the Landsat 7 ETM imagery provide information about soils, rock types, vegetation and soil moisture. Slope angle, aspect and drainage networks, derived from the DEM, provide valuable information about drainage catchment form and surface water channel geometry. The use of 1:18000 scale air photographs and Landsat 7 ETM imagery (replacing the Gtopo30, Landsat 5 TM and Daedalus 1268 ATM imagery used in our previous study) has permitted production of image draped DEM's at scales appropriate for practical geotechnical applications, without the geometrical distortions inherent in air photographs. The photo-derived DEM with a drape of merged 15m pixel ETM Pan, 30 metre pixel VIS-SWIR and 60 metre pixel thermal data reveals landslide textural and morphological information at 1:5000 scale and spectral information at 1:25000 scale, for various landslide complexes in the flash-flood prone, semi-arid terrain of Almeria Province. | ||
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