Research On Key Technology Of Tile Map Service & Prototype Development Based On Flex

WebGIS, a frontier direction in the field of GIS, is having a rapid development with the continuous change of the network technologies.Since Google Maps, a demarcation point in WebGIS, occurred in 2005, an obvious difference has appeared between the traditional and the current new WebGIS application: AJAX, Flex and other RIA technologies are used in this field. Expressive ability, interactive performance and other factors which retard WebGIS development have been improved greatly and clearly, especially when Tile Map Service used in WebGIS. This deeply ameliorates the capability of the web server-side and the client, upgrades the user experience in the application. However, very few people have done some comprehensive analysis and research so far about the current WebGIS application based on the RIA technology.This paper proceeds from the theoretical analysis and technological development in order to create a prototype for the whole rich client application WebGIS which uses the open sources like GeoServer as a map server, GeoWebCache as the tile map service in the server-side and uses the self-developed Flex client components to build the WebGIS client in the browser in order to show the way of using Tile Map Service as the data source provider. This is the practice to carry out the thoughts of using tile map realization in the current WebGIS application, so as to lay the groundwork for the future development of this realm.In general, this paper covers contents from the several parts below:Firstly, the Flex technology as the solution for the Tile Map Service in the client is chosen by systematical analyzing and comparing with the current RIA technologies.Secondly, the key technology of the tile map realization is discussed on the basis of the several aspects - the creation, caching and directory management of map tiles in the server-side, the selection of tile service communication interface, the design and implementation of the Flex components scheme, the organization and management of responsive tiles, services integration and scale computation in the client.Thirdly, a rich client application prototype based on the self-developed Flex components is created through setting up the open source Tile Map Service.Lastly, final summary and prospect are drawn, and content and focus should be done next has been listed.