Latitude and longitude to GEOREF
Encodes a latitude and longitude in the World Geographic Reference System () from a 15° tile down to thousandths of a minute, with the cell's bounds.
The GEOREF is NKLN2438.
- Center latitude
- Center longitude
- South edge
- West edge
- North edge
- East edge
Provenance
- Computed by
- geodesy.grid-ref.georef-forward 1.0.0, core 0.1.0
- Model
- GEOREF: 24 × 12 tiles of 15°, 15 × 15 one-degree letters, then minutes of longitude and latitude
- Accuracy
- Identical to GeographicLib's Georef class on 5,278 encodings, except that 180° E is written as 180° W
- 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: 24 × 12 tiles of 15°, 15 × 15 one-degree letters, then minutes of longitude and latitude
Accuracy: Identical to GeographicLib's Georef class on 5,278 encodings, except that 180° E is written as 180° W
When to use this: Use this when a system asks for GEOREF: it is still used in air operations and some defense products, dividing the world into fifteen-degree tiles and subdividing to minutes and thousandths of a minute. Give a latitude and longitude and it returns the reference and the bounds of the cell it names.
Limitations: GEOREF names an area whose size depends on the precision you choose, from fifteen degrees down to thousandths of a minute, and the cells narrow toward the poles. The convention writes 180 degrees east as 180 degrees west. It assumes WGS 84 and carries no height.
Worked example: GeographicLib's example point to the minute. Source: GeographicLib Georef: NKLN2438.
You enter
- Latitude
- 57.64911 deg
- Longitude
- 10.40744 deg
You get
- GEOREF
- NKLN2438
- Center latitude
- 57.641666667°
- Center longitude
- 10.408333333°
- South edge
- 57.633333333°
- West edge
- 10.4°
- North edge
- 57.65°
- East edge
- 10.416666667°
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: 21 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