Analysis And Description Of Map Symbol Graphic Rules

Map is the abstract expression of the real world.Map symbol is a graphic language of map.It plays an important role in the expression and visualization of geographic information.The current methods of expressing geographical features and drawing methods of symbolic figures are different.It is very urgent to study how to accurately and standardly describe the spatial attribute information of map objects and the symbol drawing rules of map symbols in map expressions.The map symbol description language,which is based on the graphic rules of map symbols and the geographic element expression rules,can standardize the mapping of map symbols and the expression of geometric attributes of geographic elements,realize the expression transformation of geographical elements,and improve the efficiency and quality of map mapping.This paper studies the organization of topographic map schemas,the graphic laws of map symbols,the classification principles of map symbols based on single semantics,and the basic characteristics of map expression rules.This paper summarizes the graphic structure,expression function and symbol generation rules for describing map symbols.The map symbol description language realizes the transformation of geographical elements and the application of map symbols.The main research content is as follows:First,on the basis of analyzing the organization of topographic map schemas,the laws of map symbols,and the expression requirements of the elements,summed up the map symbol description language,which specifies the hierarchical structure of symbols and graphics,specific description functions and symbolic expression rules.Second,according to the single semantics of map symbolic representations,the expressio n functions of geographic elements are classified.The feature entities are the collection of s ymbolic figures and feature attributes,and the unit symbolic functions in the geographic fea ture expression function are the expression bases of individual semantics.The basic symboli c function is the specific expression function,the symbolic symbol function is used as the gr aphing function,and the extended parameter functaion is used as an aid.The SQL statement is used to constrain the specific unit symbolic function generation rules to combine the geometrical position,atttibute information and expression of elements.To analysis the geographical element expression requirements,the formulation of map symbol expression f unction parameters and symbol drawing rules.Thirdly,use the platform MapStore,according to the rules of the map symbol description language,formulate ordinary terrain maps symbols and emergency thematic maps symbols that meet data requirements,use DLG data to make maps,and experiment the pie charts and graph charts in thematic maps.To realized the specific application of the map symbol description language.The map symbol description language formulated in this paper is the formulation of geographical information and map symbols and the regularization of symbol generation rules.The map symbol library based on the language can effectively improve the general map and the use of fixed point symbols.Map production automation,production efficiency and data quality.