An apparatus includes a unit dividing a region into blocks having a predetermined bit length and generating addition data having the predetermined bit length corresponding to coordinate data, a unit storing storage data having the predetermined bit length, a unit generating composite data having a bit length twice the length of the predetermined bit length by connecting the addition data to the storage data, and storing the composite data, and a unit repeating an operation of designating the bit length of the composite data as the predetermined bit length, instructing to generate the addition data, and instructing to generate and store the composite data. The number of different bits between a bit string of a location corresponding to the input coordinate data and a bit string of a reference location tends to increase as a distance between the location corresponding to the coordinate data and the reference location increases.