The Research Of Symbolizing Expsression On Geo-Spatial Information

With the rapid development of computer aided design technology and GIS, the art and science of map making has undertaken enormous changes. The time of map design is greatly shortened, and the workmanship of manufacturing a map has gradually shifted a combination of computer assisted drafting and printing. In the form of the symbolizing expression is also developed from paper maps to digital maps on geospatial information.Geographic information system is a geo-spatial information system focusing on map presentation. Map is recorded geographic information in the form of a graphical language, map symbol is the figurative language of map. Map symbols includes various shape of symbols, figures and characters are different in form, size and colors, which is combined. Map symbols not only can express the geo-spatial location, forms, mass and amount character of an object, but also representative the inter-relationship and distinguish between spatial objects. Map symbol express the meaning of the data of the maps, and survey information about space data, which distinguish the Geographic information system map from other environmental maps. On the basis of full analyzing cartographic symbols, it is implemented using ArcGIS Engine, which is the secondary development of ArcGIS component. And proposes map symbol of the production program and the symbolizing operation, it develop a symbolic function module for map symbolization by C#, and using the symbolizing expression.The basic theory of map symbol is comprehended and mastered the prerequisite of developing symbol in GIS successfully. The paper proposed the mathematical definition of point, line and area map symbols in cartography, and gives the mathematical definition of scale, non-scale, semi-scale symbols in cartography. According to the definitions in the visual variables of the cartographic symbols theory of set, the mathematical definitions of six of visual variables, which are form, place, color, size, density and direction, are given in this paper.In the paper, based on the characteristic and picture composition of the point, line and area map symbols is in-depth studied and analyzed, the point, line, area map symbol database is manufactured. Through platform of the geographic information system for the secondary development of components database ArcGIS Engine realized management of the map symbol, selection of map symbol, designing of map symbol, and format conversion of map symbol database. The paper handles two problems in ArcGIS platform, the design of map symbol and symbolizing expression is weak problem, map symbol file format cannot mutually transform.Finally, point, line and area of map symbols design and symbolizing expression is implemented by module. The experimental results show that the module implements designing of a map symbol and symbolic expression function on geo-spatial information.