Basic Map Reading

To begin with it is important to know that a map is only 100% accurate on the day it is surveyed. This doesn’t mean you cannot use a map dated 5 or so years back but just be aware that some features may have been knocked down or new features may also be seen on the ground that don’t show on the map. However the changes won’t be too different if you have a map surveyed in the past 10 years.

So what map is right for you?

There are many different types of maps out there. The easiest one to start using is the Ordinate Survey (OS) map. Next you have to choose the correct scale. The most common scale maps, shops will sell is the 1:50,000 and the 1:25,000.

The 1:50,000 will show you a large area and you’ll notice there will be less detail in what smaller features are on the ground, for example less popular paths, buildings and crossings. Each grid square is 2cm, this represents 1km on the ground. If you are looking to get a 1:50,000 OS map, they are commonly called the ‘Landranger’ series and have a bright pink tab on the top.

The 1:25,000 maps show twice the amount of detail a 1:50,000 map will, as each grid square is 4cm which represents 1km on the ground. In the shops this map will have an orange tab across the top and is commonly known the ‘OS Explorer’.

So for people wanting to start out exploring in the mountains choose the 1:25,000 scale OS map. It makes it easier to navigate and offers more information on the land you are on.

Grid references

The most basic type of grid reference is a four figure grid reference. Following this number will direct you to one whole grid square.

So how do you read a four figure grid reference? Well to start with, it is helpful to look at your map and notice there are numbers that run along landscape along the map and also a set of numbers that run portrait to the map. The numbers go up one for every grid square you go up and vice versa for going along.

To read a grid reference you start by following the classic math rule of going along the corridor. For example, the grid reference 04,42 on a 1:25,000 map. You start by going along to find the number 04. You then follow the grid squares directly up or directly down until you meet the number 42. Here you’ll meet the grid square 04,42.

To pinpoint a more precise location, it is favourable to use a six figure grid reference. These numbers may look intimidating, but if you break them down it is easy to follow. To start off with picture one whole grid square, now picture (or draw) 10 lines equally spaced going vertical long the grid square and 10 lines going parallel through the grid square. Each of these is 100m by 100m distance.

So say you have the grid reference 043,429. This means you find the grid square 04,42 and then go along the grid square 3 of the boxes you’ve drawn. Then go up 9 squares. This is grid reference 043,429 within a 100m radius.

Map Orientation

Being able to translate your map to the ground will make your life so much easier when trying to navigate. A few tips to help you do this are to spot 3 different features on the ground that you can see and that are on your map. Now rotate the map so each feature is lined up with the same feature on your map. You’ll begin to see everything else lining up from your map to the ground. It is really important to remember that whilst you’re out walking keep your map orientated to the ground. If you turn a corner, make sure you turn your map too.