Ever wanted to read a map, but too afraid to ask how?
Well now you don’t have to:
The purpose of grid references (GR) on a map is to allow you to tell someone exactly where you are or where something on the map that you want to identify (such as a building) is. When I say “exactly”, the grid references most of us work with ie six figure grid refernces, are accurate to a 100 metre square ie one which is 10 metres x 10 metres. This is accurate enough for most people most of the time.
As you have probably noticed, every map you are likely to come across is divided into equally sized squares. For example, the Ordnance Survey Outdoor Leisure maps with a scale of 1:25,000 which we provide for many of our British walking holidays are divided into squares which are 1 kilometre x 1 kilometre. So if you walked east to east on the ground from one side of any particular square to the other you would have walked one kilometre.
Working Out a Grid Reference
If you wanted to tell someone where on a map a large thing such as a village was (eg Kettlewell on the map I have in front of me) you need to tell them which square it is in. A four figure GR will suffice for this.
To do this:
- Go to the bottom left hand corner of the square where a virtical and horizontal line meet.
- Follow the virtical line to the top or bottom of the map and note the number eg 97 – this is called an easting. All the numbers which run across the top or bottom of the map are eastings
- Follow the horizontal line to the left or right hand side of the map and read off the number eg 72 – this is called a northing. All the numbers running up each side of the map are called northings.
- The village of Kettlewell is in grid square 9772, or in other words that is the four figure grid reference for the village.
- 6 Figure GRs
To pinpoint something smaller, such as the church in Kettlewell, we need a way of dividing up the grid square the village is in. We do this by imagining the square is divided into ten along the easting and the northing (if you buy a good compass it should have a grid on it to allow you to do this more accurately) and estimating how many of these squares the place we are describing is, first along the easting and then up the northing. Thus:
- The church in Kettlewell is about 1 imaginary divisions along the easting. So the original easting 97 now becomes 971.
- The same church is about 3 imaginary divisions up the northing. So the original northing 72 now becomes 723.
- If we put these together, with the easting always coming first, then the six figure grid reference for the location of the church in Kettlewell is 971723. In other words the church is in a square 10m x 10m to the east and north of the point GR971723.
Finding a 6 Figure GR
If someone tells you that your accommodation is located at GR568942 how do you find it on the map?
Here is the procedure:
- Divide the number into two ie 568 and 942. The first numbers are the easting and the second ones the northing.
- Go along the bottom (or top) of the map to 56 and then up (or down) this line until you come to 94. This is the grid square 5694.
- From this point count 8 of 10 imaginary divisions to the right (east) and then 2 of 10 imaginary divisions up (north).
- Where the points intersect is your location.
Tip : to remember which number on the map to read off first, those along the bottom or those up the side, think of walking along the corridor before going up the stairs.