The Effect Of Database Generalization On The Accuracy Of The Viewshed

This paper examines the effects of database generalization on the area which is determined to be visible in GIs analysis. Many different methods of generalization are possible, but here, for any cell at the target resolution, elevations are determined from: the arithmetic mean, the maximum, the minimum, and the maximum difference from the mean of the cells within the kernel, and all possible combinations of regular spacings. The resolutions studied are 0.5, 0.33, 0.25, and 0.2 of the original study area. The viewsheds determined over these different resolution DEMs are compared with a number of possible viewsheds derived by generalization of the viewshed over the original DEM. Of those tested the maximum deviation from the mean within kernel provides the best estimate of the pattern and area of the viewshed at all resolutions.