Confronto tra metodi di interpolazione per la costruzione di DTM

For the construction of Digital Terrain Models (DTM) multiple methods can be used: beginning from quoted points, obtained with direct relief or extracted from cartography, elevations in the nodes of the grid are determined, using interpolation methods of deterministic or stochastic type: the first are based on mathematical formulas, the seconds also on statistic considerations. Operating on the same data set, according to the used method the results change, for which the choice becomes fundamental because it influences quality, accuracy and successive possibilities to analyze. In this paper the results obtained in the construction of DTM from multiple methods are compared: relatively to an area in Campania Region cartographic data are considered (quoted points and contour lines) for the realization of three-dimensional models with the software Surfer 8.0, produced by Golden Software. The powerful of the interpolation algorithm in the definition of the quota is evaluated with the statistic analysis of the differences between the calculated quotas and the effective ones in the initial points, as well as applying Cross Validation. The results obtained from the applications of several methods (Triangulation with linear interpolation, IDW, Kriging, Nearest neighbour, Natural neighbour, Radial Basis Function, Polynomial regression, Local Polynomial, Moving Average) are compared.