Comparison of different interpolation methods for DEM production

Abstract

Spatial interpolation, or the estimation of the variables at unobserved locations in geographic space based on the values at observed locations, is fundamental in all geophysical sciences, first of all for the construction of digital elevation model (DEM). Several methods are available in literature for spatial interpolation and the choice of the most suitable of them for building DEM, depends on many factors, particularly on the distribution of the sampled points, therefore, on the morphology of the area to be mapped. This paper aims to choose the most appropriate interpolators for DEM production, by comparing different methods usually available in GIS software. For the purpose of developing the best performing model and comparing interpolators, a set of elevation data collected by digital vector map is used. The accuracy of interpolation methods is tested by analyzing 4 statistic parameters, which are achieved by cross-validation leave-one-out. Particularly, minimum, maximum, mean and root mean square error (RMSE) are calculated for each interpolation method considering the residual in each sampling point between measured and interpolated value.