说明：  gis的开发方法有三种，即独立开发，宿主型二次开发，基于gis组件的二次开发，其中独立开发为底层开发，不依赖于任何gis工具软件，开发难度太大，后两者是基于一种软件的二次开发，这样的二次开发则相对较简单，他的好处也是显而易见的。
(There are three kinds of development methods of GIS, which is developed independently, two times the development of host type, two development based on GIS component, which is the independent development of the underlying development does not depend on any GIS software development tools, too difficult, which is two times the development of a software based on the two development of the relatively simple, his advantage is obviously.)