Coordinate Systems
OMN4 can show the same place in different coordinate systems. Use this page as a lookup for what each system is for; use the linked Settings and Search pages for the steps.
Coordinate Systems At A Glance
| System | Best for | OMN4 use | Notes |
|---|---|---|---|
| British National Grid | UK Ordnance Survey mapping and UK paper map references. | Grid reference display, coordinate settings, and grid reference search. | BNG format details live in Grid Reference Formats. |
| Latitude/Longitude | Sharing positions with GPS devices, websites, and international mapping tools. | Coordinate display and Search entry. | Uses angular coordinates rather than metres on a national grid. |
| UTM | Grid-based international coordinates, especially outside Great Britain. | Coordinate display and Search entry. | Uses zones plus eastings and northings in metres. |
British National Grid
British National Grid is the usual reference system for UK Ordnance Survey map references. It is the format to use when a guidebook, paper map, or route description gives a reference such as NY 12345 67890.
For precision, spacing, prefix letters, and numeric easting/northing forms, see Grid Reference Formats.
Latitude/Longitude
Latitude/Longitude is widely used by GPS receivers, web mapping services, photos, and international route files. It is useful when you need to copy a position into a non-UK mapping tool or compare OMN4 with a device that reports decimal degrees.
OMN4 may display Latitude/Longitude with a chosen precision, but the underlying position is still the same place.
UTM
UTM is a metre-based grid used internationally. A UTM coordinate includes a zone, then an easting and northing within that zone. Use it when another mapping system, GPS, or dataset asks for UTM coordinates.
Display And Entry
Changing the coordinate system changes how OMN4 displays or accepts a position; it does not move routes, tracks, waypoints, or map data.