REDUCING ELEVATION ROUNDOFF ERRORS IN DIGITAL ELEVATION MODELS

A smoothing algorithm is presented for the removal of roundoff error, inherent in almost all digital elevation data. Elevation adjustments are kept within the tolerance of roundoff error, so that the resulting terrain model is not over smoothed. After smoothing, the digital elevation model is more suitable for use with algorithms that seek to automatically delineate stream networks and basins of a watershed. The algorithm is specifically intended for use with gridded data, and is particularly effective when used with elevations originating from the 7.5 min quadrangles provided by the United States Geological Survey.