A processor causes a storage medium to store three-dimensional data of a subject in a storage step. The processor selects a reference image in a first selection step. The processor selects a selected image that is a two-dimensional image used for generating the three-dimensional data on the basis of the reference image in a second selection step. The processor estimates a second camera coordinate regarding the reference image on the basis of a first camera coordinate regarding the selected image in an estimation step. The processor displays an image of the subject on a display in a display step. The image of the subject visualizes at least one of the second camera coordinate and a set of three-dimensional coordinates of one or more points of the subject calculated on the basis of the second camera coordinate.