Design and Implement a Cartographic Client Application For Mobile Devices using SVG Tiny and J2ME

摘要

The dissemination of digital geospatial data is available now on mobile devices such as PDAs (personal digital assistants) and smart-phones etc. The mobile devices which support J2ME (Java 2 Micro Edition) offer users and developers one open interface, which they can use to develop or download the software according their own demands. Currently WMS (Web Map Service) can afford not only traditional raster image, but also the vector image. SVGT (Scalable Vector Graphics Tiny) is one subset of SVG (Scalable Vector Graphics) and because of its precise vector information, original styling and small file size, SVGT format is fitting well for the geographic mapping purpose, especially for the mobile devices which has bandwidth net connection limitation. This paper describes the development of a cartographic client for the mobile devices, using SVGT and J2ME technology. Mobile device will be simulated on the desktop computer for a series of testing with WMS, for example, send request and get the responding data from WMS and then display both vector and raster format image. Analyzing and designing of System structure such as user interface and code structure are discussed, the limitation of mobile device should be taken into consideration for this applications. The parsing of XML document which is received from WMS after the GetCapabilities request and the visual realization of SVGT and PNG (Portable Network Graphics) image are important issues in codes' writing. At last the client was tested on Nokia S40/60 mobile phone successfully.