Lab 9 – Accuracy of DEMs

Like any interpolated raster surface, a DEM is derived from an array of measured points, specifically elevations.  What is important for interpolated surfaces is the error introduced during the interpolation process, thus the accuracy and predictive power of the DEM.  The accuracy of a DEM can be determined by comparing interpolated values to known/measured co-located values.  These points can be surveyed after the DEM is created or can be withheld from the interpolation process and used to validate the model.  One method of collected data for DEM generation is via LiDAR.  To check the accuracy of LiDAR-generated DEMs it is important to test several land cover types individually, as they may have different relative inaccuracies.