The Design And Research Of Map Symbol Database System Based On GIS

Compared with MIS, the main characteristic of GIS lies in geo-spatialinformation management, one of whose critical subjects is how to constructgeo-spatial database, thus, map plays an important role in geo-spatial dataacquisition just because of its nature as the main source of geographic data and themain presentation of GIS production. Further, map symbol is the basic means ofmap presentation, which can not only show the location, shape, mass and amountcharacter, but also illustrate the inter-relationship between objects. Map symbolforms the language of map and its main presentation method, so map symbol playsan important role in GIS. GIS is a geo-spatial information system based on map,no matter what manner to show geo-spatial information (computer screen oranalog map), its aim lies in offering geo-spatial data in geometry form such aspoint, line, fill and solid, etc. Thus, abundant symbol database of point, line and fillin GIS is needed. So while developing applied GIS, it is necessary to offerpowerful and open symbol database to meet its need.In the paper, some productions achieved about map symbol research arediscussed below:Firstly, design and implementation of multi-scale topographic map symboldatabase systemThe Map Symbol Database System is one of the essential modules ofGeographic Information System. As a fundamental research subject, it has beendeveloping rapidly with the development of Information Technologies. It isespecially significant to design all-around, systematic, precise map symboldatabase in GIS application. In order to manage and output canonical multi-scalemap, it is necessary to set up a integrated map symbol database in GIS software.Multi-scale topographic map symbol database is developed based on ArcGIS inthis thesis. At present, there are four main ways to design symbol database in mapsymbol database related to GIS all over the world. Multi-scale topographic mapsymbol database system adopts the two methods of them as follows: the firstmethod, popular method, is implemented by way of combination, move, and zoomof the basic symbol from system and customized simple symbol (i.e. point symbol),thus, developing complex symbol to meet cartography, i.e. complex line andsurface fill symbol. The other method is implemented by secondary development。Complex symbol is customized using ArcObjects, and some symbols arecustomized using the symbol-making function supplied by ArcMAP in this system.The map symbolization function is invented. Map symbol is encoded, and itsattribute data is managed using ODBC(Open Database Connectivity)in MicrosoftSQL Server in this thesis, thus it can improve compatibility and mobility of thesystem, as well as the speed. Secondly, design and implementation of map symbol COM COM is becoming the mainstream method in software technology, which hasformed the fundamentals of new generation GIS, greatly influenced GIStechnology and its application. As the weakness of the mobility of multi-scaletopographic map symbol database system, the map symbol database with bettermobility should be developed. Map symbol can be divided into three classes: pointsymbol, line symbol, fill symbol. Individual data attribute of map symbol (datamember)and operation method(operation function of corresponding to datamember) are encapsuled in symbol object class by encapsulation and inheritanceof Object-Oriented Technology in order to reduce repetition of code, redundancyof data and improve the efficiency of symbol design. The higher class, symbolclass, is summarized on the basis of the three symbol object classes. Anythingimaginable can be drawn with enough parameters because of the function ofcustomizing symbol and drawing function by way of GDI in MapObjects. So mapsymbol database COM is set up on the base of the two kinds of technologiesdiscussed above. Point symbol, line symbol, fill symbol are designed, andautomatic object file of every class is set up respectively. The finished symboldatabase COM can be used to GIS based on MapObjects. Thirdly, academic research of 3D map symbol and perspectives of mapsymbol in the future 3DGIS is attached broad importance to GIS community. With thedevelopment of science and technology, there is critical limitation in presentationof geo-spatial information with 2D symbol, thus, the rapid development of 3DGISnecessarily leads to the researching of 3D map symbol. 3D map symbol is definedbased on the definition of conventional map symbol. The map symbol is dividedinto 3D point symbol, 3D line symbol, 3D fill symbol and 3D solid symbol. Data...