Coordinate Systems

This page explains the main coordinate systems you are likely to see in OMN4.

Grid References

Grid references divide the map into labelled squares and then narrow the position within that square. They are common on British and Irish mapping and are often the quickest format to use with paper maps.

Latitude and Longitude

Latitude and longitude describe a position using angular values on the globe. This is the most widely shared format across apps, websites, GPS devices, and emergency location tools.

UTM

UTM divides the world into zones and gives positions as eastings and northings within each zone. It is widely used in outdoor navigation, surveying, and international mapping.

Which One Should You Use?

• use grid references if you mostly work with paper mapping in the UK or Ireland
• use latitude and longitude if you need a format that is recognised almost everywhere
• use UTM if your workflow or map source expects it

Your choice affects how positions are shown and entered, but not where anything is actually located.