Down-scaling SRTM slope based on histogram matching and slope distribution model

Terrain parameters are often extracted by down-scaling a lower resolution DEM at regional scale. The 1" SRTM (Shuttle Radar Topography Mission) elevation data is used widely at regional scale in terrain analysis. Slope is one of the most important terrain parameters. However, compared with the higher resolution slope surface, slope based on 1" SRTM elevation data reduced because of the relative lower resolution. Slope extracted from 1" SRTM was down-scaled in Shaanxi province of China in this paper in order to improve the data utility. The method of histogram matching and the theory of slope distribution model were used to develop a slope down-scaling model. After down-scaling in a reference area, 1" SRTM slope showed 95% similarity with the higher resolution slope, which improved 22% comparing with 1" SRTM slope before down-scaling. The slope data based on 1" SRTM, with better quality was obtained and is available for public use.