How do you use a map and compass?
In this article we’ll be covering 3 easy steps to use a map and compass for navigation in the countryside and in the mountains. At the end of this article you’ll be able to take a bearing using a map and compass to navigate when the way forward isn’t all that clear.
Let start with the map, first thing you need to do is to identify where you are on the map and where you want to go. Let say we are at the trig point on Helvellyn (blue triangle with a central dot – circled in blue) and we want to take the foot path that leaves the north (top) of the map.
We can’t go direct as there are some pretty serious cliffs to the north of the trig point so we need to break down the navigation stage into different legs. First we have to get to the foot path junction (circled in red) before we can head north.
The next thing we need to identify on the map is any hazards and a description of the path we will take. Some people call this the Three D’s, Four D’s or even the Five D’s. I’m a big fan of keeping things simple so lets stick with Three D’s for now.
- Description – (What will we pass on the way)
- Destination – (How will I know I’ve reached the destination)
- Direction – (Which way is it?)
I’ll start with the description as this can change our navigation strategy to get to our waypoint. It’s a quick summary of the navigation leg, we can look for ‘handrail’ features and ‘tick -off’ features we will pass, how long the leg is (in time and distance), and any dangers we need to be careful of.
Dangers: To our north is steep ground, in-fact its very steep, almost vertical in places. We want to stay away from there unless the weather is fine and we have good visibility. We can also use this feature as a ‘handrail’ feature to guide us along the path. If we stray to far north it will be very obvious that we are off track.
A description for the leg would be – From the trig point we will be crossing contour lines so we will be going down hill. The contours are fairly spaced out so the decent will be very gradual. The waypoint is on the 900m index contour so we are only dropping 40-50m over this leg. To our right will be steep terrain that we need to avoid but can also guide us.
Helvellyn is a popular mountain so the path junction should be obvious but what if it isn’t? If we can spot some catchment features on the map we can use these to confirm our arrival at the waypoint (blue circle) and prevent us going too far.
At the waypoint we will be on a a bit of a ‘col‘ (col is the lowest point between two peaks) so we should be on flatter ground with the ground to the north slowly rising to the cairns. This is in start contrast to the cliffs to the north so this should be obvious change in the landscape around us. The ground in front of us will continue to descend and the steeper ground to the north will return to our right if we go too far.
Which was do we go? In good weather that should be enough to give us a direction and the path can be picked out and followed. If the steep ground is to our right we are going the right way. If it’s to our left or if we are going steeply downhill we have gone wrong.
But if the weather is poor you may want to take a compass bearing to follow so leets take a look at how to do that.
Before we get map and compass together we are going to need to identify one more feature on the map. The blue square lines are gridlines and are 1km apart. These lines cross the map north to south and east to west. We need to find a blue line that heads north and these lines alway point to grid north. Luckily for us, there is grid line that passes right though our navigation leg. North is usually the top off the map and the map legend will detail the map orientation.
The compass is made up of a baseplate (full of useful markings and tools), the compass needle and a rotating compass housing. Most of the markings on the baseplate can be ignored in this scenario, the only one that matters is the direction indicator.
The compass needle floats in fluid and has a red half that point to magnetic north and the housing rotates to give a magnetic bearing (between 001 and 360) along with the cardinal points.
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3 easy steps to use your map and compass
Line up the long side of the compass with the direction you want to travel. Make sure that the direction indicator arrow on the compass baseplate is in the direction you want to travel.
You can use either of the long sides of the compass for this.
Rotate the compass housing so that the red and black orienteering lines align with grid north.
You may need to slide the compass back and forth a bit to get everything to line up. Once you’ve done this double check the edge still lines up and the orienteering lines are accurate. Once you’ve double checked and rechecked the compass is now set.
Add or subtract for magnetic variation.
We’ll cover this is more detail at a latter date but for now you just need to know that magnetic north (used by the compass) and grid north (printed on the map) are at two different points on the globe. The amount you need to add or subtract varies with time and location.
The map legend will tell you the amount of magnetic variation for that map at the time stated.
In the Lake District the magnetic variation is around 1º to the west so we need to add 1º to the bearing. To do this we rotate the compass housing so that our bearing of 52º becomes 53º
Now, in reality this is hardly worth doing here in the UK but in some parts of the world the current magnetic variation is significant. Albert in Canada currently has a magnetic variation of 15º to the east. In this case you would need to subtract 15º from the true bearing that your map and compass give you.
You can use the nemonic “west is best, east is least” to remember this.
*There is in imaginary line that crosses the UK where Grid and Magnetic north are both equal. This line is slowly moving eastward and within the next decade the UK will move from a westerly magnetic variation to an easterly variation. You can read more about it here on the Ordnance Survey Website
Hold the compass out, you’re all set to go!
Hold the compass out in front of you so that the direction indicator on the baseplate points away from your chest. Using your feet to move, turn around until the red of the compass needle lines up with the red orienteering lines on the bottom of the compass housing. The direction indicator now points in the direction of the waypoint.
Do you want more help with you navigation?
We have a range of navigation courses available for people like you who want to get the most out of their map and compass. We have group dates throughout the year and we also offer private 1-2-1 tuition too.