Elevation Order Isomorphism Characteristics of DEM

We discover and define the order isomorphism characteristics of DEM,then point out that the order isomorphism characteristics of elevation is one of the most important theoretical problems of DEM.Based on it,we prove that the prerequisite qualifications of order isomorphism of DEM are the topological correspondence with ground during interpolation being generated.Moreover,we demonstrate that the order isomorphism characteristics of three main interpolation methods about DEM generation.