Abstract :
Based on some 18 000 elevation points, a high-resolution Digital Elevation Model (DEM) of the low-lying Falsterbo Peninsula in south Sweden was created with the GIS-package ARC/INFO® for MS-Windows NT®. The DEM is used to visualize flooding scenarios, predicted to occur more frequently in the future due to the increased greenhouse-effect. Except for already existing elevation points, the input data set consisted of points collected through contour map digitizing and field measurements. The collection of points in the field was mainly carried out with GPS-RTK equipment, which provides high measurement accuracy (on the order of centimeters) at the expense of being sensitive to the occurrence of environmental factors such as treetops, which hinder the satellite signal. Because kriging was used as interpolation method, a variogram model had to be established. It was found that removal of clustered input points significantly improved the agreement between the actual and theoretical variograms. This, in turn, improves the possibility of an accurately interpolated DEM. The DEM grid size is 5×5 m with a vertical input resolution on the order of 0.1 m. It is concluded that a DEM constitutes a valuable tool with which flooding scenarios can be clearly visualized and particularly sensitive areas easily located.
