Get more out of Hill Walking with our Map Reading Hacks
Successfully navigating a terrain using only a paper map, a compass and the landscape itself is an Invaluable Skill for any Outdoor Enthusiast
Here we look at some fundamental map reading skills required for orienteering and other outdoor pursuits before moving on to some advanced navigation techniques.
Two of the most important things to know before you plan your first route or head off on your first trail are how to understand map scales and how to use a map and compass. Once you have gotten to grips with these two techniques, you’ll be ready to start deciphering some of the hidden treasures your paper map has to offer.
Giving A Grid Reference
A map of Ireland is broken up into 93 Discovery sheets. 75 of these are produced by Ordnance Survey Ireland and 18 by Ordnance Survey Northern Ireland. Each of these sheets is a single map, which is then divided into grids.
Both the X and Y axis of the grid are numbered making it possible to determine your location by what’s called a grid reference. Numbers going left to right are known as ‘Eastings’. Numbers going top to bottom are known as ‘Northings’. When giving a 4-figure grid reference, locate the square you are in then give the Easting number followed by the Northing number. An example of a grid reference would be 0819.
Approximating Distance With Map Scale
On the bottom of the map page there is a scale that shows how many miles or kilometres an area on the map represents. If a map has a 1:50,000 scale this means that 1cm represents 50,000 cm and 500 m on the ground. If you drew a line on the map with a pencil and measured it as 2cm, then the actual distance in real life would be 1km.
Once you have grasped this principle you’ll be able to mark out the distances of any landmarks or natural formations from your start point or from each other. Then when you encounter these features on your trail you will know how far you have travelled and how far you have left to go.
Once you have determined at what distance you encountered certain landmarks, it’s possible to estimate the pace at which you have been travelling. If, for example it takes you one hour to reach a monument that you have estimated by the scale on your map to be 3km into your journey, you can estimate that you’re travelling at 3km per hour. This can be a handy technique to know if you are aiming to finish by a certain time and want to check if you are on schedule.
Using Contours to Interpret Landscape
Contour lines are the lines on a map that connect different levels of elevation. The closer that two separate contour lines are to each other, the steeper the incline. A contour line at sea level will have number 0 written beside it. Contours will scale up and down in intervals of 5, 10 or 20 metres in elevation at a time depending on the type of map you have.
When the numbers are ascending that means an uphill slope. A group of contours representing an uphill slope would look like the following [0, 10, 20, 30, 40]. A group of contours representing a downhill slope would look like this [40, 30, 20, 10, 0]. If you saw [0,10, 20, 30, 40, 30, 20, 10, 0] you would be looking at an uphill slope that turns into a downhill slope once you reach the summit. This might indicate a hill, or a hump in the landscape.
Learn The Legend
It might sound obvious, but it’s important to get to know what each of the symbols on your map legend represents. If you find yourself lost, sometimes the easiest things to identify by sight are features such as roads, TV masts or churches. Once you can mark on the map what you see with your eyes, you’ll be back on track in no time.
Navigate Obstacles With The ‘Box’ Method
If there is a large obstacle directly blocking your path you can use the box method to navigate around it and return to your original bearing.
Before you set out on your walk, you will know your starting point, your destination and you will have taken a bearing with a compass to determine the direction you are heading. Let’s say you are travelling on a bearing of exactly 200° and see on your map that there is a small water feature in the middle of your route.
By making four 90° turns, you can ‘box’ the obstacle. For this technique, remember the phrase ‘Right Raise / Left Lower’ to adjust your bearing.
- Take a look at your map and judge whether bypassing the obstacle on the right or the left side will give you the path of least resistance.
- If your first turn is right (as in the diagram above), increase your bearing by 90°, so you are now traveling at a bearing of 290°.
- Count how many paces it takes to reach the corner of the obstacle.
- Now make a 90° left turn (which lowers your bearing back to 200°) and travel straight until you have bypassed the top right corner of the lake.
- Now make another left 90° turn so you are traveling at a bearing of 110° and walk the same number of paces you counted on your first turn of the detour.
- When you have reached the same number of paces, take a final right 90° turn and return to your bearing of 200° and continue on your journey.
Pinpoint Location With Transit Lines
Mark out two features on your map that will line up at only one point on your trail. This could be any combination of man-made or natural features, for example, a bridge and a church steeple. Now draw a line on the map that intersects both features and continues across the track you’re walking on. Imagine the intersection has a ribbon across it like at the finish line of a race.
Take a grid reference of this intersection spot to pinpoint your location.
You can set up a number of stages like this for your journey before you set out to keep things like pace and distance in check. You can then proceed to tick them off on your map or a checklist with a pencil as you reach them on the ground.
Use Attack Points
When you are trying to locate small features marked on a map such as an historical monument or a small man-made crossing over a stream, the safest bet can be to head for the nearest prominent feature.
For example, if from your map you were able to determine that there was a car park near the feature you were looking for, head to the car park and then from there use techniques like pacing, distance and transit lines to find what you seek.
It’s not always possible to stay on your original compass bearing, or to travel ‘as the crow flies’ for the entirety of the trail because of obstacles. When planning out your route, you can mark a number of these “attack points” that will break the journey up into smaller stages that can be easier to navigate.
Whatever your level of experience, make sure that you know how to stay safe. Read our Safety in the Outdoors tips before you head off on your next walk.
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Disclaimer: Walkers use these tips entirely at their own risk. No responsibility can be accepted by landowners or by Ordnance Survey Ireland, for any loss, damage or injury caused or sustained during walks.