Convert coordinates from GGRS87 (EPSG:4121) to WGS 84 (EPSG:4326) — official EPSG transformation parameters, accuracy and area of use, with a free in-browser converter.
The EPSG Geodetic Parameter Dataset defines 1 transformation between GGRS87 (EPSG:4121) and WGS 84 (EPSG:4326). Its parameters, accuracy and area of use are listed below.
| Parameter | Value | Unit |
|---|---|---|
| X-axis translation(tx) | -199.87 | metre |
| Y-axis translation(ty) | 74.79 | metre |
| Z-axis translation(tz) | 246.62 | metre |
The same transformation with common GIS tools and libraries:
from pyproj import Transformer
transformer = Transformer.from_crs("EPSG:4121", "EPSG:4326", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)geographic system using latitude and longitude on an ellipsoid · Area of use: Greece - onshore
+proj=longlat +ellps=GRS80 +towgs84=-199.87,74.79,246.62,0,0,0,0 +no_defs +type=crsMore about EPSG:4121 →
geographic system using latitude and longitude on an ellipsoid · Area of use: World (by country)
+proj=longlat +datum=WGS84 +no_defs +type=crsMore about EPSG:4326 →