关于地理信息系统的空间数据模型。为了能够利用地理信息系统工具解决现实世界中的问题，首先必需将复杂的地理事物和现象简化和抽象到计算机中进行表示、处理和分析。-About GIS spatial data model. To be able to use GIS tools to solve real world problems, first of all necessary things and the complex phenomenon of geographical simplify and abstract to be represented in the computer, processing and analysis.