Openlayer地图开源库的高阶应用，是对beginner的补充和淬炼(Nowadays, OpenLayers is the most complete and powerful open source Javascr ipt library to create any kind of web mapping application. In addition to offering a great set of components, such as maps, layers, or controls, OpenLayers offers access to a great number of data sources using many different data formats, implements many standards from Open Geospatial Consortium)