Abstract: A method of judging a house change based on a comparison between high-resolution images or DSMs acquired from an aircraft is incapable of determining the house change in the region in which the DSM or the like is acquired for the first time. A house region in which a house exists is extracted from a judgment target region based on house polygon data acquired in advance at a time point T0. A feature region in which a feature exists is extracted based on a DSM acquired at a time point T1 after T0. The house region and the feature region are compared to obtain a difference region therebetween. The difference region is presented, to a judge, as a candidate region of house change occurrence between T0 and T1. An orthoimage data of an above-ground feature is combined with the candidate region for display.