Research On Incremental Updating Method Of Vector Land Cover Database

Land cover data is the important basis of global change research, ecological environment assessment and macro-control analysis, the updating period for land cover database directly influences the success of related study and macro decision-making. As land parcels usually cover the whole surface along with complicated structure, the existing updating methods are difficult to update the land cover database automatically (semi-automatically). After analyzing the domestic and abroad research about incremental updating, a set of incremental updating methods for vector land cover database is proposed in this paper. The main research work includes:(1) After studying the traditional GIS data organization models, considering the processing requirement for the updating of land cover database, the author designs a representation model for vector land cover data following the OGC specifications and related dynamic updating operations.(2) Analyzing the generated reasons and characters of numerous sliver polygons which exist in the vectorization of classified data, an algorithm of merging sliver polygons based on attribute-similarity degree is introduced. The comparison among the methods based on area, attribute-similarity degree, and combining attribute-similarity degree and area are made with the experiment result, and a proper method to process sliver polygons is selected.(3) After analyzing the existing incremental information organization model and related incremental updating methods, an incremental information organization and updating method for vector land cover database based on topological relation is designed.(4) A land cover database incremental update prototype system is developed by using Visual Studio2008development tools. The related updating experiments are realized using Shanxi land cover data in this system, which proves the feasibility of the theoretical algorithm mentioned in this paper.