Measuring Distance

Measuring Distance is important for navigating in the mountains as it tells you how long and how far you will be walking for.


All hill walking maps, such as the Ordnance Survey Discovery Series, are covered with a series of horizontal and vertical lines, which makes a grid of boxes.

Each box is 1 km from side to side and 1.5 km diagonally from corner to corner.

To roughly estimate distance between two points, look at how many grid boxes lie between the points. If there are two boxes then the distance is approximately 2 km.


To accurately measure distance between two points, use the millimeter ruler on the side of your compass to measure the distance in millimetres.

On a 1:50 000 scale map 1mm is equal to 50m.
So if you measure a distance of 6mm on your map that would be equal to 300m on the ground.

On a 1:25 000 scale map 1mm is equal to 25m.
So if you measure a distance of 6mm on your map that would be equal to 150m on the ground.