An image processing apparatus, an image capturing system, an image processing method, and a recording medium are provided. The image processing apparatus: obtains a first image in a first projection, and a second image in a second projection; transforms projection of at least a part of the first image corresponding to the second image, from the first projection to the second projection, to generate a third image in the second projection; extracts a plurality of feature points, respectively, from the second image and the third image; determines a corresponding area in the third image that corresponds to the second image, based on the plurality of feature points respectively extracted from the second image and the third image; transforms projection of a plurality of points in the corresponding area of the third image, from the second projection to the first projection, to obtain location information indicating locations of the plurality of points in the first projection in the first image; and stores, in a memory, the location information indicating the locations of the plurality of points in the first projection in the first image, in association with the plurality of points in the second projection in the second image.