Error statistics for slope and aspect when derived frominterpolated data

Error models of slope and aspect of a terrain are presented. Such data are often extracted from a geographic information system (GIS), which may contain information from digital maps and remote sensing images. Although the sources of these data are usually of diverse resolution, all of them are usually resampled to refer to the same resolution. The authors examine the error associated with such data because of subsampling. The error distributions are modeled empirically