Sunday 1 December 2013

The Scale of Things...

I've just moved this post from my old Wordpress blog, as I think it's worth keeping out there for walkers to read:

Learning how to use a map and compass should be seen as an essential skill for anyone venturing out into the countryside. I’ve heard so many people say things like ‘I always go with someone who knows where they’re going’, or ‘I leave all that map and compass stuff to my friend/husband/wife’, or even ‘I only go walking to places I’ve been before’ that it can start to feel like the whole walking fraternity is perhaps just following in the footsteps of one person who just happens to have been there before.

There are so many arguments against these comments, including that there’s no adventure or sense of achievement in only going somewhere you’ve been before, or going with someone else who has. For me the most important message I try to get across to outdoor folk is the fact that if the ‘nominated navigator’ in your group should have an accident or fall ill during a walk, who is going to know where you are and where to go to get help?

So, now is your chance to learn something about maps. Today we’re going to look at the scale of maps, and the bewildering variety of maps available to buy.



Scale
The scale of the map is a measurement used to compare the map itself and all the features on the map, to the land mass it represents, and all the features on the ground. A simple scale given on a map might be written as 1:50,000. But what does this actually mean? Well, slightly simplified, 1:50,000 means that everything on that map is 50,000 times smaller than what it represents on the ground. And that’s all you need to know. So, on a map with a scale of 1:50,000 you can measure out any distance on that map and it will be 50,000 times smaller than the actually distance on the ground.
The 1:50,000 scale is one of the most commonly used scales in mapping in the UK. The others that we tend to use a lot for walking are 1:25,000 (so everything on the map is 25,000 times smaller than on the ground), and 1:40,000 (everything is 40,000 times smaller on the map than on the ground).

Buying a map
You go into a shop selling maps (often outdoor equipment shops, but you can buy them in some post offices, newsagents, tourist information centres, even pubs and cafes), and quite often there will be an array from which to choose. Where do you start?
Well, apart from the obvious starting point being that you want a map of the area you want to go walking in, there are two main map manufacturers in the UK. The Ordnance Survey, and Harvey Maps.

Let’s start with the Ordnance Survey

One of the most commonly used maps in the UK is the Ordnance Survey’s 1:50,000 scale. They have produced a range of maps at this scale that covers the whole of the UK, and this range is known as the Landranger series (left in the photo above). Landrangers are widely available, and have a pink cover. They are superb for planning walks, cycle rides, country drives, in fact anything that involves going outside. The Landranger maps show all public rights of way too, so you can use them whilst actually out on a walk. The downside of the Landranger series is that these maps do not show field boundaries. So all those walls, hedges, fences, ditches, etc. are not shown on the Landranger. So, in practice you might know that a public footpath goes through an area of land, but the map won’t tell you which side of a fence or hedge the public footpath is on.

Then we come to the Ordnance Survey 1:25,000 scale maps. At this scale the Ordnance Survey are able to show all those field boundaries, so you can easily work out from the map which side of the fence you should be walking on – bearing in mind of course that hedges get removed, and new fences do get erected too, but generally you can work out where they are on the map and the ground. The Ordnance Survey originally had a series of maps called the Pathfinder at 1:25,000 scale. These had a green cover, and the whole country was mapped at this scale by the Pathfinder series. The unfortunate thing with the old Pathfinders was that the map itself wasn’t very big. So, if you were going out on a longish walk, you might need two or three maps to cover the route. The Ordnance Survey realised that this wasn’t great, and so devised the Outdoor Leisure series, with yellow covers (2nd from the left in the photo). The Outdoor Leisure series is still at 1:25,000 scale so has all the benefits of the Pathfinders, but each individual map covered a much larger area of ground, and some of them are even double-sided. So, the one criticism that most outdoor folk had about the Pathfinders was eliminated. Well, not quite. Unfortunately the Outdoor Leisure series was only produced to cover the most popular walking areas of the country, so if you wanted to go walking in Snowdonia, the Brecon Beacons, the Lake District, the Cuillin on Skye, or the Cairngorms, for instance, you could get an Outdoor Leisure map that would cover your walk. However, should you fancy a stroll in the Shropshire Hills, Assynt, the Scottish Southern Uplands, or huge areas of lowland Britain, as an example, you had to either buy a fist-full of Pathfinders, or just use the Landrangers at 1:50,000 scale. Eventually the Ordnance Survey made the bold move to do away with the old Pathfinders altogether, and started to produce a new series of maps at 1:25,000 scale that would cover the whole country, using maps that were big enough to be useful for a day’s walking or more. The Explorer series was born. The Explorer series has all the advantages of scale, and detail, that the Pathfinder and Outdoor Leisure series boasted, and now covers the whole of the UK. These Explorer maps have an orange cover (middle map in the photo).

So, lets just recap on Ordnance Survey maps, and what they are most useful for. Generally speaking, most walkers in England, Wales, or lowland areas of Scotland use the 1:25,000 scale, and that means buying either an Explorer map, or the Outdoor Leisure (which still cover the main walking areas) – note that apart from the cover colour, these maps are exactly the same in terms of scale and detail. In the Highlands of Scotland the Landranger maps are still very popular. That is because they cover a much wider area (so you get more map coverage for your money), and there are a lot fewer field boundaries in the Highlands, so no need to worry about being on the right side of a hedge! Also, as the Highlands doesn’t have a network of public footpaths and bridleways (you have a right to roam in Scotland), even if you do find a hedge or a fence, you can legally be on whichever side of it you choose – even though some landowners wish this weren’t the case, and will tell you otherwise!

Which Ordnance Survey map series do I use? Well, as pointed out above, for walking in England and Wales, or if I’m going to a small Scottish island where I want the extra detail shown, I use the 1:25,000 by choice. For longer walks in the Highlands I tend to go for the Landranger series. For planning walks at home, I use the Landranger series first and foremost, then swap to the Explorer or Outdoor Leisure for finer detail planning.

And now we move on to Harvey Maps

The cartographers at Harvey Maps have realised that there is a lot of information on the Ordnance Survey maps that the walker doesn’t need, and that can actually make the map look cluttered. So, they have stripped down the map to only show features that are useful to walkers. And what’s more all Harvey Maps are waterproof! No more big map-cases getting tangled around your neck, and no more bulky laminated maps being too big to fit into a jacket pocket. For a while the maps Harvey produced where at a scale of 1:40,000, which can take a little bit of getting used to at first. They then produced the Superwalker series at the scale of 1:25,000 (2nd from the right in the photo) which is brilliant. These maps look good, have relief shading so you can see height detail much more easily, and have contours in either grey or brown to tell you whether it’s scree or vegetation underfoot. Now that’s user-friendly! More recently Harvey Maps have started producing a new series called the British Mountain Map (on the right in the photo). This is back at the 1:40,000 scale, which gives a happy compromise between the lack of detail of the Ordnance Survey’s Landranger series and a bigger area coverage than you get with a 1:25,0000 scale map. The other great thing about Harvey Maps is that they cover mountain regions, rather than just a square of land, so it is much more likely that all parts of your walk will be on the one map, unless you are on a mammoth backpack. The British Mountain Maps are on a material called XT40, which is completely waterproof, and tear-resistant too, and the more I use them, the more I love them. The Superwalker series is now being produced on something called XT25 which I guess is very similar if not the same as XT40 – I haven’t had one in my hands yet, so can’t comment! So, what’s the downside of the Harvey Maps, and why don’t we only use them? Well, the answer to both these questions is that Harvey Maps are only available for certain parts of the country. They cover a lot of the most popular walking regions of the UK, and a lot of long-distance routes too. But if you fancy striding out in the Yorkshire Wolds, or the Preseli Hills, you’ll have to buy an Ordnance Survey.

OK, so that’s map scales and types in detail. So what do I buy?

Well, given the overall coverage of the country, I like to plan with a Landranger on my knee. For use out on the hill, if a Harvey Map is available for the area, I’ll go with that every time. If not, it’s either OS Landranger (for the Highlands), or OS Explorer/Outdoor Leisure for the rest of the UK.

For our navigation courses, we use a combination of maps so you can get your hands on different types and different scales!

Check out our website for details of our next available map and compass courses Wild Walks Wales. These include ‘Safety in the Hills’, which is a 1-day course covering all aspects of keeping safe while out on a walk, including basic navigation, and ‘National Navigation Award Scheme’ courses which run over a weekend, and are tailored to different levels (Bronze for beginners, Silver for intermediate, and Gold for advanced navigators). These NNAS courses include assessments at the appropriate level. We also run Night Navigation courses, for more experienced hillwalkers, throughout the winter months.

I hope this has been useful to you, and hope to see you on the hill in the future!


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