Abstract
The effects of changes in DEM resolution on Japanese mountain topography are examined from the viewpoints of geomorphometry. First, in order to examine the influence of resolution on the histogram of slope angles, the changes in the descriptive statistics value as a function of resolution are plotted. As a result, DEM with 25-m resolution or more high-resolution DEM should be used when calculating slope angles. Next, we examined the appropriate resolution from the viewpoint of magnitude frequency distribution of landslides that greatly contributing to slope formations in Japanese mountains. From this examination, it was clarified that 5 to 10-m resolution DEM is needed to observe slope forms in and around landslide area. However, more high-resolution DEM is preferred to analyze the detail of landslide topography. At last, we evaluate the effects of DEM resolution using the accuracy of drainage network construction. We could judge that the 10-m DEM is enough to extract the drainage network for practical applications. From these results, we need 25-m DEM at least, and about 5 to 10-m DEM ideally for geomorphometry in Japanese mountains. Therefore, it is desired to be equipped with around 5 to 10-m DEM acquired by direct measurement for geomorphology.
