Study On Map Symbol Of Object-oriented Space Model

In the system of GIS, symbol should express geography phenomenon correctly and reasonably, Satisfying the output request of map, also should satisfy the request of analysis, inquiry, process and memory of feature. the tradition symbol system of point,line,region only consider the effect of map output, can not satisfy the demand of GIS. The paper which is based on object oriented special model, Obtaining from the object entity and the characteristic of the symbol, summarizes the symbol and Proposes a new system of symbol template to solve the question .The author carries on the analysis and comparison to the feature of big scale Topographic diagram, expresses spot,line,region and its the combination geography phenomenon by point symbol,linear symbol,region symbol and zonal symbol, and propose four Template concepts including Entity template,cell symbol template,normal symbol template,meta-map symbol template. The entity template is composed of cell symbol template, the cell symbol template is composed of normal symbol template, and normal symbol template is composed of meta-map symbol template. Entity symbol can be divided into one or many symbol cell, which is the minimum dell and has specific meaning. Regulation of the organization and definition of basic feature of symbol cell is described by normal symbol template, which has point template,linear template,region template,color filling template,freely label template,zonal template, and corresponding the form of entity symbol template regulate the frame and basic organization rules of basic meta-map. In order to solve geometric reference of complicated symbol cell and definition, the symbol cell gives a group of assistant definitions .According to this kind of symbol system, symbol storehouse of Survey control point, inhabitant, industry and mining building, transportation, pipeline, river system, boundary, landform and soil texture, vegetation is built, which shows a great ability of symbol expression. The definition to entity symbols is feasible,integrated,rigorous,extensible and flexible. this kind of symbol system Can express complex entity and the big scale topographic diagram, and satisfies the integration management request of geography information.