Grid References are formed by the blue lines which go up and across maps.
They will allow you to describe a point or area to someone who can’t see your map.
On the 1:25K maps the blue lines form squares, each side of which is 1km.
To give a Grid Reference you read the horizontal Easting (East to West) and the vertical Northing (North to South).
Remember this: Along the corridor and then up the stairs.
A four figure Grid Reference is fine if you just want to describe an area (in this case which is 1km square).
Of course in many cases you’ll want to give a more precise location, so you’ll need to add another reference by dividing the map square up into smaller squares, the roamer at the edge of your compass can be used for this.
This is grid reference 613 577
Don’t forget: Along the corridor and THEN up the stirs
Note if using a grid reference for something important, e.g. a Mountain Rescue call, then it is “really” useful to give extra information.
So, in the above example it would be, “We are on the foot bridge at SH 613 577”
SH is the map number which is printed in Blue at the top of the map.