When considering the various extent of error values, different mean error values
in files entering the local cluster analysis and different size of maximal value in the
clusters of high error values (Table 2), however, we find out that clusters of high
errors in high-quality DEM which at first sight appear to be more extensive, in
reality cover much lower values of errors than aerially smaller clusters of high
errors derived from low-quality DEM. Moreover, taking into account the structure