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Convert ETRS89 to ETRS89 + St. Marys height

Convert coordinates from ETRS89 (EPSG:4937) to ETRS89 + St. Marys height (EPSG:9430) — official EPSG transformation parameters, accuracy and area of use, with a free in-browser converter.

Direct link to this transformation: epsgtransform.com/transform/epsg-4937-to-epsg-9430

Official EPSG transformation from ETRS89 to ETRS89 + St. Marys height

The EPSG Geodetic Parameter Dataset defines 1 transformation between ETRS89 (EPSG:4937) and ETRS89 + St. Marys height (EPSG:9430). Its parameters, accuracy and area of use are listed below.

ETRS89 to ETRS89 + St. Marys height (2)

EPSG:9585±0.01 m
Method:
Geog3D to Geog2D+GravityRelatedHeight (OSGM-GB)
Area of use:
UK - Scilly Isles onshore
Scope:
Reversible geoid model transformation.

Grid file: OSTN15_OSGM15_GB.txt

Reversible alternative to ETRS89 to St. Marys height (2) (code 7716).

Convert EPSG:4937 to EPSG:9430 in code

The same transformation with common GIS tools and libraries:

from pyproj import Transformer

transformer = Transformer.from_crs("EPSG:4937", "EPSG:9430", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)

Source: EPSG:4937 — ETRS89

geographic system using latitude, longitude and ellipsoidal height · Area of use: Europe - ETRF by country

+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs +type=crs
More about EPSG:4937 →

Target: EPSG:9430 — ETRS89 + St. Marys height

compound horizontal + vertical reference system · Area of use: UK - Scilly Isles onshore

+proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +geoidgrids=uk_os_OSGM15_GB.tif +geoid_crs=WGS84 +vunits=m +no_defs +type=crs
More about EPSG:9430 →

Frequently asked questions

How accurate is converting ETRS89 to ETRS89 + St. Marys height?
The most accurate official EPSG transformation between these systems is accurate to about ±0.01 m within its stated area of use. Browser-based converters approximate datum shifts with Helmert parameters; for surveying-grade work apply the official transformation (including the grid-shift files listed below) 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.
Need the reverse? Convert EPSG:9430 to EPSG:4937 →