google地图//api说明http://code.google.com/intl/zh-CN/apis/maps/documentation/index.html//类参考文档http://code.google.com/intl/zh-CN/apis/maps/documentation/reference.html51地图//api说明http://api.51ditu.com/docs/mapsapi.html//类参考文档http://api.51ditu.com/docs/mapsapi/reference.htmlmapBar//api说明http://union.mapbar.com/api