Tokyo Datum
lastmod 2018-08-17created 2014-07-095 edits
Tokyo Datum (Japanese Geodetic System, (旧)日本測地系, Tokyo Datum) is a coordinate system based on the Bessel ellipsoid (ベッセル楕円体, Bessel). It was used until April 1, 2002.
Since April 1, 2002, Tokyo Datum 2000 (Japanese Geodetic Datum 2000, 日本測地系2000, ~JGD2000, ~ITRF94), a coordinate system based on the ~GRS80 ellipsoid, has been in use.
Ellipsoid parameters
Bessel Ellipsoid a = 6377397.155m rf = 299.1528128 1
-
a: semi-major axis (長半径) -
rf: inverse of the flattening (偏平率)(rf = 장반경 / (장반경 - 단반경))
Difference in coordinate origin
- JGD2000 x coordinate = Tokyo Datum x coordinate - 146.414m
- JGD2000 y coordinate = Tokyo Datum y coordinate + 507.337m
- JGD2000 z coordinate = Tokyo Datum z coordinate + 680.507m
世界測地系と日本測地系での経緯度原点
| 経度 (longitude) | 緯度 (latitude) | |
| 世界測地系(2002年) | 東経139度44分28秒8759 | 北緯35度39分29秒1572 |
| 日本測地系(1918年) | 東経139度44分40秒5020 | 北緯35度39分17秒5148 |