Using geostatistics and G.I.S., for DTM’s assessment

[Abstract] The main objective of this study was to examine topographical information by means of geostatistical techniques. Moreover, the spatial dependence of point measurements was used in order to assist in making digital elevation models (DEM’s). The survey was conducted in cultivated land. Topographical data were measured for two different fields which size is 2.24 Ha and 0.62 Ha using an Abney level. The continuity of the spatial distribution of point measurements has been evaluated using geostatistics. The analysed data sets showed a lineal trend. After removing the trend experimental semivariograms were calculated and scaled by dividing each of them by the value of their respective variances. Variogram models with small nugget effect and a spatial component described well the residual data resulting from trend removing. The curve fitting technique used to adjust models was jack-knifing. Effects of sampling density during data collection was critically evaluated. Once topographical data were estimated on a fine grid through kriging, contour maps were obtained and subsequently transported to the GIS. The methodology used to expand information from point to landscape with the geostatistical techniques has proved itself very useful