Many existing national coordinate systems are based on reference figures of the Earth that are generally outdated and are restricted to a particular country, making cross-border or regional mapping, development and project planning very difficult.
现有的许多国家坐标系统都基于基本已过时且局限于特定国家的地球基准数字，很难依靠它们进行跨境或区域制图、开发和项目规划。