基于JFreeChart与ArcGIS JavaScript API的专题制图

Thematic Cartography Based on JFreeChart and ArcGIS JavaScript API

基于目前迅速发展的WebGIS技术,结合专题地图智能应用的特点,提出了一种JFreeChart图表组件与ArcGIS JavaScript API相结合动态制作网络专题图的方法。该方法利用JFreeChart强大的图表引擎功能,在服务器端构建统计符号库,以JSON和XML等形式获取专题统计数据,根据统计数据特征自动选择适宜表达方式,生成统计符号后与客户端请求的WMS或WFS服务图层叠加生成专题图。以浙江省在线动态专题地图制作软件为例,对JFreeChart与ArcGIS JavaScript API结合制作网络专题图进行了应用。实践表明,此方法以网络服务形式提供,动态制图功能扩展更灵活,统计符号类型丰富,能满足不同专业背景用户的制图需求,体现了专题地图智能化的应用。

A new method for Web cartography, which using ArcGIS JavaScript API combined a chart component named JFreeChart, was put forward to make thematic mapping easier in the context of Web. According to this method, the statistic map symbol base was constructed based on JFreeChart in the server end and the statistic data was transferred to the server by the form of JSON and XML, then the appropriate visualization expression was pushed on the basis of the characteristics of statistical data and diagrams were constructed. Finally, a com- plete thematic map was composed of diagrams from server and some geographic base maps in the client. At last, Zhejiang Online dynamic thematic map production software was taken as an example to show the application of various technique of Web visualization of statistic data based on this method. It showed that the visual- ization system and method of visualization functions were worthy of spreading.