GEOREF to latitude and longitude
Decodes a World Geographic Reference System () code to the center and bounds of its cell.
The GEOREF cell is centered at 57.649108333°, 10.407441667°.
- Center longitude
- South edge
- West edge
- North edge
- East edge
Provenance
- Computed by
- geodesy.grid-ref.georef-inverse 1.0.0, core 0.1.0
- Model
- GEOREF as in GeographicLib's Georef class
- Accuracy
- Identical to GeographicLib's Georef class (within 1e-13°)
- Notes
- None
- Cites
- Karney, C. F. F., GeographicLib, GeographicLib GARS and Georef classes
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: GEOREF as in GeographicLib's Georef class
Accuracy: Identical to GeographicLib's Georef class (within 1e-13°)
When to use this: Use this to turn a GEOREF reference back into coordinates: it gives the center of the cell the code names and the cell's bounds, so you can plot it or check its extent. It is the counterpart to the encoder, so a reference written in an operations order or a legacy product can be plotted without hand-decoding the letter pairs, and the bounds show how much ground the code actually commits you to.
Limitations: The reference names a cell rather than a point, and the cell can be large: a four-character code is a one-degree box. The center is the middle of that box, not a surveyed position. Coordinates come out as WGS 84. A code with an odd number of digits after the letters cannot be split into a latitude and a longitude part, and is rejected rather than guessed at. Nothing in a GEOREF carries a height, a datum, or a time.
Worked example: NKLN2444638946. Source: GeographicLib Georef documentation example.
You enter
- GEOREF
- NKLN2444638946
You get
- Center latitude
- 57.649108333°
- Center longitude
- 10.407441667°
- South edge
- 57.6491°
- West edge
- 10.407433333°
- North edge
- 57.649116667°
- East edge
- 10.40745°
Review: Not yet independently reviewed by a geodesist.
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Changes
- 2026-09-19, changed: The GARS, GEOREF, Maidenhead, and USNG tools are stable, both directions. They reproduce NGA's GARS band definitions, the Wikipedia GEOREF (NAS Patuxent River) and Maidenhead (W1AW) examples, and the FGDC USNG Washington Monument, and match GeographicLib, pygeodesy, an exact Maidenhead reference, and NGA GEOTRANS on thousands of points. Results are unchanged apart from the fix below. Changelog
Checked against: 22 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- GeographicLib GARS and Georef classes, Karney, C. F. F., GeographicLib, GeographicLib 2.x. GARS.cpp and Georef.cpp: encoding, decoding, and precision rules. Read free.
Terms
- GEOREF: World Geographic Reference System
- An aviation grid reference that names 15° and 1° squares with letters, then gives minutes of longitude and latitude. Source: GeographicLib
GEOREF — World Geographic Reference System
An aviation grid reference that names 15° and 1° squares with letters, then gives minutes of longitude and latitude.
Source: GeographicLib