日本的东京坐标系与世界大地坐标系 (ＷＧＳ)有约 50 0ｍ的差异。从 1 982年起 ,日本在海图上标示东京基准与ＷＧＳ的改正数。 1 997年以后 ,试验出版ＷＧＳ84格网的港湾图。其出版的《航路指南》中的位置数据都用ＷＧＳ84和东京基准两种方法表示。从 2 0 0 0年 4月开始正式出 Japan’s Tokyo coordinate system has a difference of about 500 meters from the World Geodetic System (WGS). Since 1982, Japan has charted the Tokyo Benchmarks and the WGS corrections on its charts. After 1997, a harbor chart of the WGS84 grid was published. The publication of the “route guide” in the position data are used WGS84 and Tokyo benchmark two ways. From April 2000 officially released