AbstractTopographic information can be digitized in several ways. Sampling may be surface-random or surface-specific. Surface-random sampling includes grids, contours, and randomly-located points. In this study, grids and surface-specific sampling are compared with reference to the problem of estimating certain geomorphometric parameters.Results of empirical comparison of the methods over six selected topographic samples are presented. The assumption of a linear relationship between grid spacing and grid error is used to estimate the grid spacing which would be required to produce the same average errors as the surface-specific point samples. For the three parameters used, these hypothetical grids require more digitization time and computer storage space than the surface-specific point data sets.