Abstract: A data structure for a graph, which is composed by points and line segments connecting adjacent pairs of the points, respectively, of a two- or three-dimensional object comprises a set of point data of the individual points, each of the point data of the points consists of a clockwise or counter clockwise circular ordered adjacency list written in storage areas of a storage medium individually allocated to the point. The adjacency list describes a plurality of adjacent points associated with the point sequentially according to a circular adjacency order as viewed from outside of the graph with address pointers to the storage areas allocated to the adjacent points, respectively, and location pointers associated with the address pointers, respectively, to storage locations of adjacency lists of the adjacent points, respectively, where an address pointer of the point is written.