An image processing apparatus comprises an acquiring section that acquires DEM data indicating digital elevation of each lattice-shaped area in a predetermined map region, a selecting section that selects at least one of a plurality of line filters that filters data which is continuous in one direction in the map region and a plurality of matrix filters that filters data constituting a two-dimensional region in the map region, a filter processing section that conducts filter processing of the DEM data acquired by the acquiring section by a filter selected by the selecting section, and an outputting section that outputs the DEM data after being filtered in the filter processing.