The present invention is provided with: a coordinates calculation unit (161) that, from distance measurement point (P)-related data indicating the distance to and the angle of a plurality of distance measurement points (P) and the coordinates of a laser beam irradiation reference point, and from the attitude angle of an aircraft (2), calculates coordinates of each of the distance measurement points (P) on a corresponding image among a plurality of images; a feature point extraction unit (162) that extracts feature points for each of the images; a distance calculation unit (163) that calculates, for each of the distance measurement points (P), the distance to a nearby feature point among the feature points extracted by the feature point extraction unit (162) on the basis of the coordinates calculated in the corresponding image by the coordinates calculation unit (161); and a necessity determination unit (166) that deletes unnecessary data from the distance measurement point (P)-related data on the basis of the calculation result of the distance measurement unit (163).