Abstract: A method for D-TIN or constrained D-TIN generation by integration of distance transformation(DT) and region adjacency graphics(RAG) is proposed.Its basic idea is that Delaunay triangulation is the dual structure of the Voronoi diagram.Concretely,DT is used to obtain Voronoi diagram while RAG is used to find spatial relationships between discrete points on building Voronoi diagram,which is helpful to from the D-TIN.Compared to the typical method with which mathematical morphology is used,our proposed method is capable of increasing the efficiencies approximately 57.70% and 56.64% on average for D-TIN and constrained D-TIN generation respectively.