What is the required DEM spatial resolution topographic correction?

[rese_support]

A DEM spatial resolution comparable to the image resolution is sufficient for most applications. Even if the DEM pixel size is larger than the image pixel a clear reduction of topographic illumination effects is usually achieved. However, areas of steep slopes that are smoothed in the coarse-resolution DEM may lead to artifacts. In practice we often have to live with DEM resolutions of 50 - 100m, because higher resolution DEM's are not available or too expensive.