The Research And Apply On Data Dictionary Of Map Symbol

Map symbol is the key method to express the characteristics, types and distribution rulesof geographic elements in GIS and occupies an important position in the representation andvisualization of geographic information. Its drawing style and symbolic mechanism aredecided by map symbolic defined model. Now, different GIS and cartographic softwares usedifferent symbolic model. The composition and structure of map symbol and the features ofmap symbol base are also different.With the study of the integrated product of DLG and mapmore mature, the normalization and standardization of map symbol representation is moreimportant to ensure the consistency and accuracy of the geographic information’s cognitionand the sharing of map symbol. It becomes the key content to study the normalization andstandardization of the map symbolic defined model and map representation.Based on the analysis of the characteristics of map symbol, DLG and the integratedproduct, it proposes map symbolic model with unit symbol as foundation, geometric locationand attributes provided by spacial data, accocaiated with map symbol and realizes the staticgeneration of symbol. It builds a map symbol system under the model to classify and definethe symbols. To the problem of the normalization and standardization of map representation,it confirms the rules to represent by unit symbol and codes the map symbol. It also confirmsthe objects described by the map symbol data dictionary and ensures the contents and stylesof it in detail. It explains the expression, coding and parameter setting of map symbol.Based on the model raised by the paper, the corresponding element symbol is made andhas been applied in practice. Under this model, it has realized the symbol making of the bigscale maps and applied in map generalization. The map product has met the reqirements ofthe normalization and standardization. At the same time, it has achieved synchronous updateof the map data and DLG data, which can enhance the efficiency of update. It can realize thethe data transformation in AutoCAD, which has advantadges in the transformation losslesslyand sharing of information. The map symbol data dictionary provides technique references tomap symbol making and foundation to standarlization research of map symbol.