Tuesday, 28 October 2014

Map or GPS?

I'm sure you've all seen it in plenty of Facebook threads. Someone invites opinion or advice on brands of GPS and they get a regular stream of "learn to use a map" comments. Clearly, using a GPS is (a) cheating, unless everyone else has one, and (b) dangerous, because it leaves you at the mercy of the elements when it breaks down. Discuss. Well, here's my tuppence worth.

I learned to navigate when in my teens. The scale of the OS maps in use at the time was one inch to the mile; you could also get six inches to the mile, but as these were neither a practical nor economic proposition for most activities, the "one-inch" was the one everyone used. With a bit of instruction and plenty of practice in a range of areas and weathers I learned to be safe and reasonably competent. These are skills that once learned and practised, you don't forget.

Silva compasses look pretty much the same nowadays as they did fifty years ago but the maps have steadily improved. The OS 1:50,000 series (although fully metric, these were still referred to as the "one-and-a-quarter-inch" series by most people on their introduction) gave more useful detail than the one-inch, then later the 1:25,000 seemed amazing, with almost too much information for simple navigation at times. Harveys really cracked it when they started producing their 1:40,000 series, not only a perfect scale but waterproof. So no excuse for not being able to find your way around these days.

Then came GPS. At first, although you could get a hand-held version the accuracy was so poor that in most cases it was still more precise to use a map. OK for sailing your boat or flying your plane, where I guess you can plot your route so that the odd hundred yards doesn't make much difference, but not good enough to stop you walking over a cliff in the fog. But then the Berlin wall came down, the Americans took the scrambling off the satellite signals available to the masses, and  GPS can now tell you where you are  -  exactly. And that does make a difference.

I've played over the past 7 or 8 years, and come to the conclusion that wherever a GPS can take you, you could have got there equally well with a bit of steady map and compass work. And most of the time I still prefer to use a map. The screen on a GPS is pretty small, and I like the fact that the map gives you the big picture at the same time as the detail you're interested in at the moment, rather like running in daylight when you can see your surroundings as well as the next few feet compared with running at night when your vision is restricted to the pool of your headlamp. But I think there are a few situations where the GPS is worth its weight because it can save you a lot of time.

The first of these is in wild weather. When it's blowing so hard you can barely stand, the rain is torrential, the snow blizzard-like, these are the times when using a map and compass is a bit of a trial. Gettting yourself into a position where you can hold enough of the map steady to read it, transferring bearings between map and field, what to do with it as you cover the next hundred yards or so, I'm sure you've been there. Much easier with the GPS in your pocket, or held up your sleeve, pull it out, flick the light on, a quick check on where to go next, and away.

Another situation is when you are navigating across featureless ground in poor visibility. If you can see a hundred yards or so, no problem. Decide the bearing, fix your mark (rock, tree, whatever), go to it and repeat. If it's dark, depends how good your torch is.  At fifty yards visibility it's still doable, though with twice as many marks to make, and each mark brings with it a possible slight error. Once you're down to ten or fifteen yards it gets tricky.  The overall error grows and it may be hard to find useable marks. If there are two or more people you can use each other as marks, but on your own you don't have that luxury. I sometimes wonder at folk I see trying to follow a bearing by just looking at their compass needle. We all drift to one side or the other when we do this (if you don't believe me try it on a park or football pitch, see if you can walk a straight line looking only at your compass without glancing at your surroundings).  Under these conditions the only safe way to go is to aim off aggressively to reliable features, which may end up with you covering up to 50% more ground than by the optimum route, in addition to all the time taken faffing. With a GPS, just checking that you are to the right or left of your desired line is lightning fast, and you take the shortest possible route.

Finally, I like to use a GPS in forestry plantations. Forestry roads, tracks and paths often change frequently, swathes of trees are felled, etc, so what you see on your map is often not what you are faced with on the ground. A GPS will confirm changes instantly rather than your having to stop and work out what has gone on.

So to go back to the title, for me it's map and compass and GPS, use the tool most appropriate for the conditions. For what it's worth I use a Garmin etrex 30, weighs just 150g, simplicity itself to use and the standard AA batteries last all day. I don't take it on every event. In "Trail" races such as the West Highland Way or the Hardmoors and Lakeland 50/100 events you are mostly following clear trails, and on any trickier bits I think there are more than enough features to make a map at least as fast, if not faster than the GPS. But in the "mountain" type races, where you are often picking your own route over intermittent tracks or trackless ground, I think it's worth the weight in the pack.

So what about the critics? First, is using a GPS in an event "cheating"? Well, I've already said that in certain conditions I think it can save a lot of time, so if you use one and another runner doesn't, then I think you have an advantage, regardless of how good the map skills of the other guy may be. But I've also observed that some of the people who criticise the use of GPS are quite happy to go out and recce the route of an event they've signed up for. Now if using a GPS is a bit like taking a calculator into the exam with you, then a recce of the route is like seeing the exam paper well in advance; you can't have it both ways. So where I am is that if the event allows a GPS and I think it's worth it, then I take it. What actually constitutes cheating is decided by the Race Director. For a few years I'm sure there will be some traditionalists who make a point of going without a GPS (or without poles for that matter!). We've seen it a lot in the climbing world; artificial chockstones (nuts), sticky rubber boots, chalk, and numerous other developments have been seen as "cheating" by reactionaries to start with, then they get accepted and the world moves on.

Secondly, does using a GPS put you in potential danger if and when it breaks down? Well, no it doesn't, if used sensibly.  You can see from what I've said above that  I think a GPS gives you an extra club in the bag, to be used in addition to your map and compass skills, not instead of them. I believe that no-one should undertake an event in any of the UK's wilder areas until they are fully competent to navigate using a map and compass. I'm not sure that I really approve of the recent trend for marking some events, or even the use of "roadbooks", as these suggest that you can get away with not being able to navigate. I understand where this comes from. In the US and much of continental Europe, walking in the hills is different. You follow a well-marked trail until you come to a junction, where there will be a signpost. A map is hardly necessary unless you choose to go "off piste". You don't need to be able to read a map to enter an event. But that's not the UK tradition; we've (so far) been brought up to understand that when you wander off into our hills, you should be able to bring yourself safely down again, and it would be a real shame to lose that ethic.

The single most important principle of navigation is to know where you are now.  It's a rule we all break at times, often through over-confidence or laziness, and when we do we are reminded why it's so important. Because if you know that, it doesn't matter whether your next step is to pull out a GPS or a map. Either, with the right skill, will get you to where you want to go next.

Happy navigating, whatever your preference!

1 comment:

John Kynaston said...

Another very interesting post! I have been using the navigation feature on my Suunto Ambit this year and found it is really helpful in providing a back up to keep me on track (most of the time!)