Sensitivity of Topographic Correction to the DEM Spatial Scale

Topographic correction has become very important in areas with rugged terrain. Many studies have suggested that a digital elevation model (DEM) with an inadequate spatial resolution undesirably removes topographic effects. In this letter, a scientific experiment was performed to explore the sensitivity of the topographic correction to the DEM spatial scale based on remote sensing images simulated with a 5-m resolution DEM. Topographic corrections with different DEM resolutions that ranged from 5 to 500 m were performed for simulated images with resolutions of 30-500 m to estimate surface spectral reflectance. Five representative topographic feature points were selected for the analysis. The results demonstrate that the sensitivity to the DEM spatial scale primarily originates from the spatial heterogeneity of the terrain and from the spatial resolution of the image that is topographically corrected. More complex terrain is associated with topographic corrections that are more dependent on the spatial resolution of the DEM. In general, for 30-m resolution remote sensing images, the DEM spatial resolution must be at least 10 m, whereas for 90- to 500-m resolution remote sensing images, a 30-m DEM can achieve the required topographic correction accuracy.