A spatial filter for the removal of striping artifacts in digital elevation models

Elongated topographic artifacts, such as the striping production artifacts described for USGS 7.5-minute DEMs, can result in globally biased estimates of slope and aspect. As such, developing methods to reduce these artifacts and their resulting biases is important. This study presents an algorithm for the mitigation of these artifacts, using Terrain Resource Information Management (TRIM) digital elevation models (DEMs) of the Fort St. John Forest District, in British Columbia, Canada, as the test bed. The algorithm uses a theoretical error model, where elevation measurement errors are assumed to be autocorrelated along the collection lines of the photogrammetric model, and takes advantage of the entry order of DEM points to apply a sequence of spatial filters to the elevation. A probability function is used to constrain the elevation changes to an acceptable range. The algorithm is effective in mitigating the artifacts' effects on slope and aspect while preserving the original topographic detail.