Map Reading Tips – Part 2 – Grid references

Why use grid references?

Grid references allow a person to give an exact location in the outdoors, this system is ideal if you find yourself in need of help and need to call mountain rescue. The pictures below are all on 1:25 maps, however, this same system is used on 1:40 and 1:50

Map section from OS maps

The picture above shows a blue grid system that covers the map, left to right you can see the numbers 66 to 71, these are called eastings, the numbers on the right run from 58 to 61 and are called northings, whenever we quote grid references we always give the eastings first followed my the northings.

Map section from OS maps

So lets look at the map above, we are trying to guide emergency services to the cairn which is bottom center right of the blue square. We know from the blue numbers and following the eastings first rule that our four figure reference is 7060, however, this will only reduce the area to 1km squared, we need to reduce the search area so we use a 6 figure reference.


The above diagram shows how we intend to provide a six figure reference. The square in the picture must be split into 10 squares by 10 squares, this will pinpoint our location down to 100m. The cross in the grid is the location of our cairn, first we give the eastings which are 707 and the northings which are 601, this will give a six figure grid of 707601.

Every map also has a suffix or code so that people know what map your using. The code is found at the four corners of the map and in this instance is SH.

Map section from OS maps

So we now know the 6 figure grid reference and the map code, the map code is always first followed by the eastings then northings, using this system we now have our reference.

Six figure grid reference – SH707601


More Information can be found at the Ordnance Survey website by clicking here

Thanks for reading, this blog was developed as part of National Map Reading week.

For more information about me and my navigation courses visit my Facebook page.



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