Map Reading
Ordnance Survey Maps : 5 different types of maps used the most for scouting purposes are the Explorer Maps which are ideal for outdoor activities.
Others are Landranger, Travel (Tour, Roads & Routes).
Conventional signs : can be found on any map
’s legend and vary from map to map. List how features on the ground are represented on the map, such as different types of roads, railways, general features, archaeological & historical information, vegetation, heights and natural features.
What do these two symbols mean?
Grid References : Grid lines that are all one kilometre by one kilometre run across all UK maps. You can use these to pinpoint a position on the map using the numbers that run north/south and east/west.
A four figured reference will take you to the one of the squares covering the map then a six figured number will give you the exact location within that square.
When reading off a grid reference you should always go along the horizontal then up the vertical or “Along the corridor and up the stairs”. Using the roamer on the compass can help to improve accuracy.
What is at 544 683?
What is the grid ref of Museum, People’s Palace on Glasgow Green?
Scale : Two scales of map 1:50,000, 1cm=50,000cm on the ground (or 500m)
& 1:25,000, 1cm=25,000cm on the ground (250m)
On a 1:50,000 scales map grid lines cross every 2cm, which provides a good overall view, the contours stand out better but can miss certain details.
Whereas on a 1:25,000 map the grid lines cross every 4cm meaning you get good detail on features like streams and lochs.
Diagonal across the grid line box is approx 1.5 kilometres

Contours : are the brown lines on the map that represent lines of equal height along the ground, they are spaced 10m apart on OS maps. They are vital for planning the best route to take. The closer they are together the steeper the terrain. They can also be used to see the shape of the terrain, where there are ridges, valleys, cols (links of roughly equal height between two peaks) and spurs (a lower peak than the main summit). All contours rise from a geographical baseline which is normally described as sea level; in the UK this is the mean (average) sea level recorded in Newlyn, Cornwall between 1915-
1921.
Compass :
Can be used to measure distances on a map.
Using the scales along the edges, be careful to use the correct scale if you use the cm on the compass remember the that on 1:50,000 1km=2cm and on a 1:25,000 1 km=4cm
Work out grid references i.e roamer
Find north
The red point on a compass will point to magnetic north (drawn by the Earths
Magnetic field), this is not a constant location and varies from year to year and depending on your location in the world). The Grid line on the map will point to
Grid North, which is close to True North. Because of this we must add or subtract a deviation to the compass bearing when using it with a map.
Deviation will be shown for the location you are walking in on the individual map.
Metal and other objects with their own magnetic field can affect the needle so be careful what you are near when using the compass.
Objects such as
Setting the map
You can set your map to North by using landmarks shown on the map to those you can see around you or use the compass, hold the compass flat and find north, line up the compass and grid line on the map until they run parallel with each other. You can then use what you have learnt to find you position on the map.
Calculating bearings, map to compass (to follow)
Lie the compass on the map along the route you wish to take, then turn the compass housing around till the orienting line run north and parallel with the grid line.
When taking a bearing from position a to b in the UK always add for magnetic deviation. So a bearing of 60° taken from a map with 3° deviation will be 63° to walk along.
“Grid to mag, add”

To walk along the bearing you have got from the map, hold the compass in flat in your hand, turn until the red end of the compass needle lines up with the north on the compass housing and your direction of travel is then shown by the arrow at the front of the compass.
When using a compass to navigate you should always be doing visual checks on the landscape to make sure you are heading in the right direction. Any error when taking the bearing will become worse the further you walk. An error of 6° will result in you being 200m wide of your target after 1km of walking.
Calculating bearings compass to map (back bearing and triangulation):
The reverse is true for taking a bearing with the compass and putting it on a map.
“Mag to grid, get rid”