Part 1: Reading a Map

At first glance maps can look hectic, and they do hold a lot of information, so it is useful to think of the features on a map as members of one of three categories; built features, natural features and features that represent height above sea level.

All maps will have a key which lets you know what all those dots, splodges and lines on the map mean in reality and it is worth familiarising yourself with this before trying to read any map. Every map is different but some common features are shown in the Key below. This key, and all other examples in this blog series come from the Harvey maps of Scotland (www.harveymaps.co.uk).

Note the height features top left, water features below that and built features top right. The scale of the map (in this case 1cm on the map represents 25,000cm in reality) and the direction of north can also be shown in the right-hand side of the Key.

Understanding built and natural features is fairly straightforward. We can all picture a building, a tree a road or a body of water and pick these out on a walk but understanding the lie of the land through features that represent height above sea level is trickier and can become important when out on trips in areas with less obvious landmarks. It is these features we will focus on.

Spot Heights and Contours

Spot heights are small dots on the map that have the height above sea level written next to them. They tend to be found at the top of mountains, next to important sites and at saddles between two peaks. Understanding where the higher and lower ground is on the map  helps us to build up a picture of the terrain and understand which way is up! Check out these examples.

Note the spot hights highlighted by the red circles and the contour heights by the red lines. From this info we can tell that the slope drops from Castle Hill (728m) down to Rothiemurchus Lodge at around 450m

Contours are the numerous brown lines seen in the example and they link together terrain which has the same height above sea level. The difference in height between contours can be found on the key (typically between 10 and 20 meters) and the exact height of some contours is shown regularly on the map (for the ones in between you have to use those math skills!).

The way one contour line squiggles across the map and its relationship to its neighbours can tell us a lot about what the terrain looks like in reality. When contours are very close together the slope is steep (and potentially hazardous), when they are further apart the slope is gentle. Below are some recognisable terrain features and how they are represented on a map.

Ridge Lines & Valley Floors

These two features are often mistaken for each other on a map as they both appear as a series of ‘V’ shaped contours stacked up together.

The best way to clarify if the ‘V’ shaped contours represent a valley or a ridge is to understand which way is up and down using the height information of the contours. Remember if the height information isn’t immediately obvious find some nearby spot heights or contour heights. Once you have established which way the slope falls, we can now tell whether the ‘V’ shaped contours represent a valley or a ridge. If the ‘V’ points downhill then the feature is a ridge line and if the ‘V’ points uphill then the feature is a valley. Take a look at these examples.

First take a look at the contours to work out where the top and bottom of the terrain is. Note Sron Riach at 1113m top left and the 600m contour bottom right. The Red ‘V’s pointing downhill show the line of a prominent ridge. The Purple ‘V’s pointing uphill show two valleys either side of that ridge. Also note the streams flowing in the bottom of the valleys and the path along the ridge line.

Summits

Summits appear as a series of concentric shapes with the contour rings getting progressively bigger as you move downhill away from the summit.

Remember to look out for those spot heights at the top of the summits. You will also likely find a number of ridge lines (those ‘V’ shapes) extending out from the summit like fingers of a star.

Saddles

Also known as cols, passes or bealachs (Scotland) these important features mark the meeting point for two valleys and two ridges.

The contours can appear complex here and tend to be heading off in many directions but if you look for the ridges and valleys first an understanding of the broader picture can be built up.

The red circles above show two summits (concentric circle contours) and using the height features on the map we can then identify two ridges and two valleys all congregating at one point. The saddle.

Convex Terrain – getting steeper as you go downhill

On the map convex terrain can be identified by the contours getting progressively closer together as you move downhill.

In real life if you were standing at the top of this feature the slope would drop away in front of you hiding a lot of the terrain lower down.

Concave Terrain – getting less steep as you go downhill

In reverse to the feature above, concave terrain ca be identified by the contours getting progressively further apart as you move downhill.

In real life standing at the top of this feature you would see the whole slope falling away in front of you like standing at the top of a big skate ramp.

As you travel from A to B in the example to the left the contours get closer together so the slope gets steeper. This is a convex slope. As you travel from A to B in the example to the right the contours get further apart so the slope is getting gentler. A Concave slope.

Summary

• Take time to understand the ‘Key’ and start by identifying built and natural features on the map.
• Work out the height between contours from the key and start to pick out spot heights and contour heights on the map.
• Once you start to become comfortable working out which way is up and down using the contour heights you can now start to pick out some of the obvious features mentioned above.
  • Ridges – ‘V’ points downhill
  • Valleys – ‘V’ points uphill
  • Summits – spot heights and concentric circles getting bigger downhill
  • Saddles – where two ridges and two valleys meet
  • Convex slopes get steeper (contours closer together) downhill
  • Concave slopes get gentler (contours further apart) downhill

The most important thing is to spend time reading and looking over a map and practicing to pick out the features. The more time spent doing this at home the easier it will be reading the map the next time the wind and rain pick up on your next adventure.

In the next part of the blog post we will look at how to plan a route using a map including how to understand distances and some tips for safely executing your plan.

Part 2: Planning a route

In Part 1 of this navigation series, we became familiar with reading a map and identifying features and terrain. Now in Part 2 we can use this understanding to plan a route in order to execute a safe adventure in the hills.

The map sample below is part of the Harvey Maps British Mountain Series. For more information on these great hiking maps check out the Harveys Website here.

In our example we will plan a route from the train station in Crianlarich (point A) to the summit of Cruach Ardrain (point B) making a horseshoe traverse of the mountains two northern ridges. The first step is to describe the route.

Describe the route

This simple step helps you to identify the key features of your route, points where important route-finding decisions need to be made and helps you picture how your day will play out. Once you have developed a bit more experience this step can be done mentally whilst looking over your map but for now it helps to write it down. Think about including important information that can be read from the map such as built features, terrain features, heights and directions based upon the points of the compass. Keep the sentences short and clear. Below is a description I have written for our route to the summit of Cruach Ardrain.

Leaving the train station in Crianlarich follow the forest road first east before quickly turning south through woodland. After crossing underneath some electricity cables look out for and take the second turn off to your left at approximately 270m altitude (almost 3 contours, each at 15m, above the bold contour marked 225m. 225+(3*15) = 270m).

Follow this path for approximately 1.5km. The path will become less well defined along its length as indicated by the dashes on the map. The Allt Coire Ardrain river will be seen or heard flowing to our left and on reaching the end of the defined path we will leave the forest and enter onto open ground as indicated by the change in colour of the map from green to yellow.

Continue following the course of the Allt Coire Ardrain until you reach a small stream flowing down from your right. At this point head South West and follow the small tributary stream uphill to its source at an area of wet boggy ground. Directly uphill and South West of this point a small pass in the ridge will be seen as defined by the shape of the contours. Head for this small pass at 675m. At this point you will be able to look both East and West down into two valleys and South up a defined ridge.

Follow the defined ridge uphill where a hill path will be found. Follow this along the ridge which gradually turns East and climbs more steeply to defined summit of Cruach Ardrain at 1046m

From the summit descend steeply North East to a small pass at 855m before climbing again along a complex ridge through crags to Stob Garbh at 959m. Continue along the crest of the ridge over the top of Stob Coire Buidhe at 857m to the ridge end at 701m. This section is pathless but the ridge crest should suffice as a guide.

A small stream can be followed North West from point 701m down a steep slope passing into woodland at 375m and eventually meeting a forest track at 240m (225+15). Picking up this track turn left (West) and after about 1.5km and having crossed a bridge over the Allt Coire Ardrain river turn left onto the forest track you started the day on. Follow this back to the train station.

As you can see by writing down a description, we have already identified important sections of the route, where there are turn offs or paths to follow, where features dictate our route and at what heights we should find these. Writing these down in a small notebook for reference on your trip is helpful if the weather changes and for comparison with your navigation aids such as altimeter and compass. Don’t worry if you are not familiar with these tools as we will cover their use in Part 3.

Handrails and catching features

As you can see from the description above features like ridge lines, rivers, paths and boundaries between types of vegetation can be very useful for describing a route and for navigation. These linear features are easy to identify on the map and in real life. We can use these linear features in two different ways.

The first is as a ‘handrail’. In this scenario we use the linear feature as a guide to walk along. In our example we use the river and stream as a handrail when we walk along the side of it. We also use a ridgeline as a handrail and follow its length.

In the second scenario these linear features can be used as a ‘catching feature’. This is when we take note of the point at which we cross a linear feature and can use this point as an indicator that we need to change direction or take another course of action. In our example we use the ridge line as a catching feature on the way up to tell us to change direction. On the way down the path is a great obvious catching feature to tell us to stop descending and follow the path to the left.

When you next plan a route think about how linear features can help you as handrails and catching features when you are next on the hill.

Break the description in different legs

The description is pretty wordy so it helps to break the journey down into more obvious legs that can be described simply by their Height Gain or Loss and Distance. I tend to define my Legs by a change between climbing and descending or on reaching a major terrain feature like a ridge or river. Below are the Legs I have broken our example into. Distance is measured using the scale of the map and height from the contours. Remember to check out the key on the map to make sure you are measuring correctly.

Having defined our distinct legs we can start to build up a picture of which sections may prove harder than others and thus take longer. We also now know the overall distance we expect to cover and the height we will have to climb. This information helps us to make some prediction as to how long our trip may take.

Timing – using timing rules and monitoring progress

Naturally the time you will take to complete your adventure will depend on how fast you will be walking. With some experience you can start to predict what speed you tend to walk at on different terrain and a timing card like the one pictured below is a great tool for this.

When I am out with clients, I tend to err on the side of caution and plan for walking 3km on the flat each hour and then add 1 minute for every 10m of height gained. So for our route above we travel 12km which will take 4 hours at 3km/hr (12/3 = 4) and we gain 1002m of height adding 100 minutes onto our journey (1002/10 = 100). In total our journey should take 5 hours and 40 minutes (4hr + 100mins = 5hr 40min).

This gives us an idea of when we should start our journey so that we finish before dark or before weather changes. It is worth calculating the timing for each leg in the same way so that you can monitor whether you are walking faster or slower than your predicted times. Knowing if you are on or behind schedule allows you to make important decisions like when to abandon your original goals and choose a shorter route if you are moving slowly or if you are moving well to potentially extend your trip.

Safety – bad weather options, escape routes and leaving a route plan with a friend

Now that we have an established route planned and we have a rough idea of how long it may take we have some good information to leave with a friend in the form of a route card. Should an accident happen on your adventure this route card will alert your friends and potential rescue teams as to your intended plans and aid in any rescue attempt. A route card should show your rough route and direction of travel, your intended start and finish time and at least one intermediate time, say at a summit as well as your name and phone number and the number of people in the group. Check out the route card below for our example route.

It is also worth thinking about some escape routes from your intended plan that can be used if the weather changes or if it becomes clear that you will be unable to complete your intended route. You can add these to your route card as well. In the example above they are in black.

Summary

• Describe your route – Use straightforward sentences and include information that can be read from the map (heights, features, handrails and catching features) as well as directions using the points of a compass and up or down.

• Break the route into legs – With clear start and end points, the distance between the points, the height gained or lost and any important notes.

• Predict the timing of your route – Calculate how long you think each leg will take based upon km travelled each hour with the addition of time for height gained. Start conservatively and after a few trips you will begin to build up an idea of your normal speed.

• Make a route card to leave with friends – Include your route and any escape routes, timings and name and phone number.

Taking time to plan your route well will make it easier to avoid any navigation errors when you are out on the hill and will hemp massively if bad weather comes in and you need to navigate in poor visibility.

In the next blog we will look at how to use a compass to aid your navigation should poor conditions catch you out.