Walking on Dartmoor. Earle John
that is hidden!
You can of course buy smaller individual sheets of the 1:25,000 maps for both First and Second Series but you will need quite a few of them to cover longer walks. However, this scale is ideal for Dartmoor as many more details are shown as well as walls and small differences in height, both important when navigating on the moor.
Finally, Harvey Map Services has two Dartmoor maps (north and south Dartmoor) in its Mountain Recreation Series with a scale of 2.5cm to 1km (1:40,000). They use an orienteering style of presentation with different colours to indicate vegetation. The physical features of the moor are all important on this map and there are very few place names printed; the result is a very clear and uncluttered map.
Next you will need to consider the conventional signs; the shorthand of maps. Most sheets have the conventional signs printed on them. I was taught to repeat like a parrot that contours are imaginary lines joining all places of equal height. This may be so, but more important is to be able to read the contours so that you can see if you are going up or down or if it is a steep slope or a gentle slope and where there are valleys and gullies. It does not take long to get the feel of the land from them.
The parallel lines printed on all the maps that you are likely to use are the grid lines. Each line has a number to identify it. The numbers of the lines that run up and down the sheet increase as they move toward the right or east and the lines are called eastings. The ones that run across the map increase as they move up the sheet or north. They are called northings. Each of the squares created by the grid lines is 1km by 1km. The diagonal across the square from corner to corner is 1. 5km. Once you know this it is very quick and easy to estimate distance. Regardless of the scale of the map the grid squares are always 1km by 1km. Obviously the larger the scale of the map the larger the square will be on the map.
The other more important use of the grid lines is to give grid references and I shall be using these in the Guide to pinpoint places. You must always give the eastings first and than the northings. So to give the position of a large area such as a village you need only give a four figure reference to indicate the square. For example, the village of Holne lies in the square 70 eastings and 69 northings, in other words SX 7069. However, it is usual to give six figure references and to do this you will have to subdivide each square into tenths. You give the main number of the easting square followed by the tenths eastward followed by the main northing square and the tenths northward. For example, the reference for Dartmeet would be 672 eastings and 732 northings, given as just SX 672732. It must be remembered, though, that this actually represents a square 100m by 100m on the ground and if you want to become really accurate then eight figure references are better but to be honest it is almost impossible to work them out correctly. You should always prefix your grid reference with the grid letters as similar references recur at intervals of 100km. For Dartmoor these letters are SX but as I am only referring to Dartmoor I have not included them.
A lot of your navigation will be done visually and to do this you must orientate your map. I assume that you know where you are when you start! So to orientate your map you identify some features in the countryside such as a tor, a forest boundary or a building and you turn your map until the features are lined up with their representations on the map and everything else will fit into place.
Now you need to consider the compass. There are many different makes on the market ranging from simple ones costing £7.00 to £15.00 to the more sophisticated costing up to £60. You will need a proper navigating compass as the small button compasses you can buy are no use. They should have a clear plastic base like a protractor with a swivelling capsule and at least a luminous needle – other luminous points are useful for night navigation.
Clapper Bridge over Dean Burn, Walk 6
You can now orientate your map using the compass. The top of the map is always true north and for all intents and purposes the easting grid lines point to true north.
First place your compass on the map with the rotating capsule turned so that the north arrow on the compass card or dial is in its correct position at 0 (or 360) degrees, and with the whole compass pointing to the top of the map (north). You can use the grid lines to help you do this. Slowly rotate the map, and yourself if needs be, keeping the compass firmly in place pointing to the top of the map (north) until the compass needle itself swings and points to magnetic north which is just 2.75 degrees in 2002, to the west of true north, in other words 357.25 degrees. Your map is now set and you should be able to identify features.
This last operation mentioned that the compass needle points to what is called magnetic north, located to the north of Hudson Bay in Canada, rather than true north and this must always be taken into consideration when navigating and especially in the next stage of compass work. By the way this magnetic variation decreases 0.50 degrees every four years.
There will be occasions where the moor is featureless or you are in thick mist or even at night when you will not be able to navigate visually either by lining up features or walking towards known points identified both on the map and on the ground. It is then that you will have to rely on your compass by taking and using compass bearings. To do this place the edge of the clear protractor part of your compass along what is called the line or direction of travel; in other words from where you are to where you want to go.
Now turn the capsule until N (north), usually shown by an arrow engraved in the bottom of the dial, points to the true north (the top of the map). Once again the parallel grid lines will help you do this. Pick up the compass and ADD, by gently rotating the capsule, what is called the magnetic variation (the difference between magnetic north and true north) which as I mentioned is 2.75 degrees in 2002. (This does decrease over the years and you should check with your map which will give the information.)
Now hold the compass in front of you and turn you body until the red (north) end of the swinging compass needle points to the north on the compass dial: this is the arrow engraved on the bottom of the capsule. The larger direction- of-travel arrow on the front, longer end of the compass, will now point at where you wish to go. Choose a landmark or a feature on this line (not a sheep or a cow!) within the limits of the visibility and walk to it without looking at the compass except perhaps for a brief check. When you arrive choose another new landmark and repeat the procedure until you arrive at your destination.
With this brief information you should be able to find your way around on Dartmoor but navigation is a fascinating subject and well worth following up and it is just as well to have more than one person in your party who is competent with a map and compass.
One final bit of advice. I should get a good large, waterproof, clear plastic map case or cover for your map, or spray it with one of the waterproofing fluids that are available. Wet, windy days on Dartmoor can quickly destroy a map!
Dartmoor letterboxes
This unique curiosity, found in no other moorland or mountainous region, was more or less started in the last century by a man called James Perrott whose grave you will find in the churchyard at Chagford.
James Perrott was known as the Dartmoor Guide and he used to take his clients to the remote and barren areas known as Cranmere Pool in the heart of the north moor. (There is yet another Dartmoor legend about Benjie Gear, by the way, associated with Cranmere Pool.) To record this achievement the walkers used to leave their visiting cards in a pickle jar that Perrott had left there in a small cairn that he built in 1854.
When you consider the costumes of those Victorian times, especially for the ladies, and the fact that there was no military road from Okehampton to within a mile of the Pool, as there is today, the walk of over seven miles over difficult moorland was certainly something worth recording.
Fifty-one years later, two keen moorland walkers placed a visitor's book there so that people could sign their names when they arrived at the desolate spot. By 1908 the numbers visiting Cranmere each year had risen to over 1700. The most famous person to sign his name at Cranmere was perhaps the late Duke of Windsor who, when he was the Prince of Wales, visited the box in 1921. The next letterbox to be established on Dartmoor was in 1894 at Belstone Tor.
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