AUTOMATED MAPPING OF LAND COMPONENTS FROM DIGITAL ELEVATION DATA

An algorithm for automating the mapping of land components from digita l elevation data is described. Land components are areas of relatively uniform slope and aspect and often correspond with ridge crests, shou lders, head slopes, back slopes or foot slopes. Aspect regions, which generally span from stream to ridge, are first identified by generaliz ing an aspect map derived from digital elevation data. The aspect regi ons are then split successively into land components by grouping pixel s above or below an automatically determined contour of elevation or ' distance from stream'. The contour approximates a slope break. The lan d components mapped in this way give a complete polygonization of a hi lly landscape and are a reasonable approximation of manually mapped la nd components.