The Methods Of Quantitative Measurement Of Geospatial Information Content In Area Map

Quantitative measurement for map spatial information is one of the basic research directions in the domain of theoretic cartography. It has been considered as an important indicator for evaluating the efficiency of map design, map generalization algorithm and the transmission of spatial information. Existing methods mainly analyze and measure map spatial information content from the aspects of diversity, difference, complexity and importance, but they have not clearly recognized the relationships between them. And the source of map spatial information, the type of map spatial information, map information content of each type and its influencing factors have been mixed and considered together, which affects the feasibility and effectiveness of these algorithms.To solve these problems, starting from the scientific definition of map spatial information, this paper takes spatial information content measurement of area map as research object, systematically elaborated quantitative measure algorithm for spatial information contained in area map. Firstly, the article proposes the essence of map spatial information is spatial difference, and give the definition of map spatial information, map spatial information content and map spatial information content measurement. Then, considering the hierarchy theory and the spatial difference, a hierarchy classification method of spatial information in area map is put forward, and they have been divided into4types:geometric information based on the difference of convex hulls, topological information based on the difference of objects, distribution information based on the difference of neighborhood and position information based on the difference of positions.Based on this idea, a quantitative measure algorithm of spatial information contained in individual area feature is firstly proposed, and specific method of calculation and realization is presented. Furthermore, a quantitative measurement method of spatial information contained in area map is established. Test results show the feasibility and effectiveness of the proposed methods. Finally, this paper summarizes main findings, and highlights further research directions in the near future.