Source: EPSG:4171 — RGF93 v1
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 →
Convert EPSG:4171 to EPSG:4807
Online coordinate converter from RGF93 v1 (EPSG:4171) to NTF (Paris) (EPSG:4807). Enter your source coordinates and get the result instantly. All transformations happen in your browser — no data is sent to any server.
The EPSG dataset defines official transformation parameters for the reverse direction. See NTF (Paris) to RGF93 v1 — the parameters are invertible.
Convert EPSG:4171 to EPSG:4807 in code
The same transformation with common GIS tools and libraries:
from pyproj import Transformer
transformer = Transformer.from_crs("EPSG:4171", "EPSG:4807", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)Target: EPSG:4807 — NTF (Paris)
geographic system using latitude and longitude on an ellipsoid · Area of use: France - onshore - mainland and Corsica
+proj=longlat +ellps=clrk80ign +pm=paris +towgs84=-168,-60,320,0,0,0,0 +no_defs +type=crsMore about EPSG:4807 →
Frequently asked questions
- How accurate is converting RGF93 v1 to NTF (Paris)?
- Projection-only conversions are accurate to floating-point precision. If a datum shift is involved, browser-based tools use Helmert parameters which are accurate to roughly 1-5 m; for surveying-grade work apply the official grid-shift transformation in a desktop GIS.
- Does my data leave the browser when I use this converter?
- No. All coordinate transformations are computed locally in your browser using proj4js. The coordinates you enter are never transmitted to any server.