The Visualization Browse Of Map Data Based On WebGIS

Nowadays the dissemination of map data is accomplished artificially. To use the data, sections and units have to employ special personnel to search for the data and transmit it by means of hard copy. However, this way of data dissemination is time-consuming and costly. With the application and development of Internet, the visualization of map data on Internet has become an indispensable stage to the network dissemination of digital map data, for it can ensure the accuracy of disseminated map data and at the same time increase the efficiency and lower the cost. Based on the phenomena , this dissertation choice the visualization of map date based on the WebGIS to study, discusses from the aspects hereinafter. Considering that the dissemination of map data is accomplished artificially, Assays the necessity of the visualization of map data on Internet. Presents the whole design of the visualization browse of map data on Internet by summing up the system structure of WebGIS and comparing the advantages and disadvantages of the five techniques used to realize WebGIS, especially ActiveX technique. In addition, this dissertation studies the realization techniques of Web, and establishes the map data flow of the visualization browse system of map data on Internet by considering the structure and feature of data in the map database. MapCtrl.ocx, a map display component with GUI is designed in the realization of the system. It can display and browse the map by combining the map database and the map symbolbase. This dissertation also presents in detail the concrete steps and techniques used in the development and realization of the component, such as component technique, data exchange, screen display, data compressing and decompressing and data encrypting and deencrypting. A visualization browse prototype system of map data on Internet is developed based on ActiveX technique. This system realizes the browsing, operating, querying and analyzing of map vector data on Internet. At last, this dissertation sums up the shorts and the next work of the system.