Convert coordinates from RGF93 v1 (EPSG:4171) to RGF93 v2 (EPSG:9777) — official EPSG transformation parameters, accuracy and area of use, with a free in-browser converter.
The EPSG Geodetic Parameter Dataset defines 1 transformation between RGF93 v1 (EPSG:4171) and RGF93 v2 (EPSG:9777). Its parameters, accuracy and area of use are listed below.
| Parameter | Value | Unit |
|---|---|---|
| X-axis translation(tx) | 0 | metre |
| Y-axis translation(ty) | 0 | metre |
| Z-axis translation(tz) | 0 | metre |
Maximum differences are 0.1m in both horizontal and vertical. Distortions in RGF93 v1 are irregular and IGN considers that no systematic transformation to the improved v2 adjustment is possible.
The same transformation with common GIS tools and libraries:
from pyproj import Transformer
transformer = Transformer.from_crs("EPSG:4171", "EPSG:9777", 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: France
+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs +type=crsMore about EPSG:4171 →
geographic system using latitude and longitude on an ellipsoid · Area of use: France
+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs +type=crsMore about EPSG:9777 →