Influence of DEM resolution on topographic correction models using spot satellite image

Topographic correction models (TCMs) are valid on satellite image data preprocessing steps. The illumination angle may be sensitive to different terrain slope and aspect conditions base on sun-terrain-sensor geometry. Although the topographic correction is influenced by the sun azimuth and zenith angle, the correction result can be equally in the same image status. By contrast, the terrain factors change with different digital elevation model (DEM) resolution in the topographic correction equations and cause a significant effect. Slope is sensitive in rugged terrain, and aspect is impressionable at flat surface at a coarse DEM resolution data. As the DEM resolution lead a distinct result on TCMs, this research is aimed to examine the impact of DEM resolution on the accuracy of terrain representation and of the gradient determined. In this study, five TCMs, including cosine correction, C correction, SCS correction, SCS+C correction and Minnaert correction models are compared by different resolutions using SPOT image data. The 5 meter DEM obtained from Ministry of the interior will be resampled to 10 to 500 meters to test those topographic models sustainability on Lienhuachih Research Center. The accuracy of five topographic correction models base on different DEM resolution will be evaluated by root-mean-square error (RMSE).