Research And Implementation Of Map Symbol Database System

Although map symbol database system has production nowadays, it still has following disadvantages: 1. symbol data can't be shared by other platform, because map symbol database system is bound up with the geographic information systems (GIS) platform. 2. symbols creating function is weak, most GIS software can't produce symbols by complex graphics, which cannot meet visualization and drawing requirements. 3. The realization of symbol data managing and compatibility is difficult because of lacking standard interface to symbols coding. So this thesis studies on design and implementation of Map Symbol Database with dealing with these problems.This thesis adopts a double-part model of symbol database system, which contains a module of creating map symbols and a module of drawing map symbols. The first module is the symbol editor separated from GIS platform. The second module is embedded into GIS platform as form of codes in charge of operations to existed symbols. The double-part model design method reduces burden of running GIS platform system, improves functions of creating map symbols by not modifying structure of GIS platform system and introduces a new idea of using the same map symbol database by different GIS platform system. In order to facilitate creating map symbols, this thesis proposes a drawing method based on graphical element with the Object-Oriented thoughts. In addition, this thesis designs general interfaces for map symbol database via coding design, creating parameter tables and managing files in order to share data greatly.The project has developed a map symbol database on the Windows NT OS and by VC++.NET platform, completed prospective task perfectly, fulfilled system function requirements and software's stability has been tested in practice.