DTD Design Of Urban Geographic Information System Based On XML

Geographic Information is fair important information in our life and work which people often use it unconsciously. We have applied Geographic Information System (GIS) in construction trades such as city planning,city control. It also will spread to other related information technology industries,for example,e-Business,automobile navigation.GIS is technique in which computer technology is used to manage geographic information. The progress of traditional Geographic Information Technology is based upon unique technique of software manufacturer,so various GIS software has its own file format. This kind of challenge contributed something on GIS technology,but at the same time,it also raised obstacles to data share which has been a problem concerned by technology experts and politicians at the end of the 20th century.In this respect,the thesis is devoted mainly to introduce extensible Markup Language (XML) technology into the construction of Urban Geographic Information System. XML originated from Standard Generalized Markup Language (SGML) is a kind of new technology,which remedies the defects of Hper-Text Markup Language (HTML). It is generally acknowledged as next generation network language. What's more,it complies with the strict grammar rules and has good preserving value nature. In addition,the technology has an advantage that display is separated from contents. So XML is powerful for data management and network information transport.Document Type Definition (DTD) should be defined before building Urban Geographic Information System based on XML. This paper analyses data type and character,then defines a simply,practicable DTD - C-XML.dtd. In order to describe the character of XML document of geographic information,the paper compiles documents respectively in accordance with Geo-spatial Data Transfer Format of Chinese,and compares with these two kinds of documents.XML documents will not be delivered through some displaying forms like screen unless other utilities are used. SVG,based on XML,is a language of displaying vector graphs. Only the documents based on XML converted to SVG canthe describing vector graphs be displayed in Browser. At the end of the thesis,a map of Chengdu downtown whose scale is 1:500 is converted into SVG form and can be viewed by IE5.0...