用mo进行二次开发时，每次启动系统都需要加载数据，这里仿照arcview中的加载工程，实现了mo中的工程保存与加载，可以记录图层的各种显示属性-used for a second round of development, each system needs to start loading data, here modeled on the ARC loading, the realization of projects mo conservation and load records sho