the gps conundrum and the vi effect

Sun, Aug 22, 2010

The other day Dawn and I were trying to remember the name of a restaurant in Glasgow that we’ve been to and neither of us had the foggiest what it was. So I fired up the phone and courtesy of a Vodafone Femto Cell which gives 3G coverage in the middle of nowhere, we used Google Maps to virtually walk down Bath Street and stand outside the restaurant, noting its name and phone number. Job done. Rewind a couple of years to where I met a bloke near the summit of Beinn a’Bhuird who had a phone he kept looking at and I’m sure he had earphones dangling too. So I suspect he was using an early form of GPS, probably a Nokia as they were popular back then but strangely he had joined me on the edge of the cliffs. I was there to take a bearing where the cliff edge turned south, so I knew exactly where I was for an accurate bearing to the summit on the featureless plateau but he had a GPS and only now I’m wondering why on earth he ended up at the same spot as me. Why didn’t he navigate straight to the summit? Leaving aside such questions, I think I was witnessing the birth of smartphone based navigation. A topic much in the news these days and tipped to knock GPS units into the void. But just how accurate and reliable are GPS’s?

With the standard six figure grid reference a map and compass are accurate to 100m. A GPS can be accurate to 4m if it gets enough satellites. That’s twenty five times more accurate than a map and compass. It’s also very difficult to follow a compass bearing across rough ground. It’s very difficult to follow a bearing in a whiteout or strong wind. In comparison, a GPS is a virtual path you can follow in any conditions. If you encounter a hazard such as a cliff, you can detour round and rejoin the virtual path without needing to step count, box and all that. If you see an interesting rock or plant off to the side you just go and see it and not have to worry about following the original bearing. You just get back on the virtual path. When you approach your destination the GPS will even sound a little alarm when you’re 100m from it or however far away you’ve set the proximity alarm. The more expensive models will even show you where you are on an OS map and in which direction you’re going. GPS? It’s a no brainer.

And yet. And yet there’s the omnipresent message that you must have a map and compass with you. Stone age tools in a digital world. But the advice is pointless if you can’t use a map and compass and I fear a new generation of walkers can’t do just that. They use a GPS like us oldies use map and compass. They’re adept at downloading routes from, say, Walk Highlands and navigating the myriad screens on the device, recording tracks, times etc but they don’t really know how to use a map and compass. How reliable are GPX files downloaded from walking web sites too? I mentioned Walk Highlands as the chap who runs it personally walks the routes and records the tracks so I trust what he puts on the site. Other sites I have no idea. But no matter how good your unit, reliable your GPX source or ninja like you are in your mastery of the device, there’s always a bejumpered beardy in the background rasping “map and compass sonny, map and compass”.

To use an analogy from the world of computers, the compass is the vi of the outdoors. vi (pronounced “vee eye”) is a tiny, almost cult-like unix text editor that comes with every unix distro from Solaris to Linux. It’s always there but it’s difficult to use. There are a plethora of graphical text editors available these days but the wise system administrator learns how to use vi. Just in case. It uses what seem like incantations to move the cursor around the document (H is left, J is down, K is up, L is right, SHIFT$ goes to the end of a line, 0 goes to the start, 132G goes to line 132, etc) but when a server goes wonky and all those fancy text editors are unavailable, the prepared sysadmin can shell in the back and rescue everything with judicious use of vi to repair configurations. That’s where the compass fits these days. It’s an arcane tool with its own spells. Do you add for mag or subtract? How many degrees do you add or subtract this year? Some people don’t even bother with the magnetic variation, even instructors. The what? The magnetic variation? Yes. What you see is very definitely not what you get. You see, the earth’s magnetic field is out of kilter with grid north. Excuse me? er, hello? Where’s he go? I was going to mention how it slides about on an icy map and the bubble. No, you really don’t want a bubble in your compass. But if you leave it on the radiator overnight the bubble will go away. Magic.

I’m not really selling the compass am I? But a wise walker will have one and know how to use it for no matter how damn good a GPS is, one of two things is going to happen sooner or later. It’s either going to run out of juice, especially if it’s a smartphone and you’re listening to music on it. Or you’re going to drop it and not be able to find it, especially in a whiteout, or it’ll get smashed on a rock. Either way you’re up poo straights without a method of propulsion. But the hecklers from the back row are shouting “you can break or lose your compass or your map”. Indeed, I’ve done both but map and compass are commodity items. They’re pennies compared with a 300 quid SatMap 10. So you carry spares. Spare map, spare compass, or maybe two if you’re a Magoo-like fumbler. You don’t carry a spare GPS. You can’t afford to.

And here we enter some murky and controversial water. Silva lose money on their popular compass I was once told by an instructor who was told by a Silva rep. They lose money on the the most important tool a walker can have. Their compass. Silva make it at a loss. It’s a commodity item that they might as well sell to make that Silva One Stop Shop. They have other income streams that let them subsidise compass manufacture and hence keep the walking planet turning. GPS manufacturers are the complete opposite. They need to sell GPS units and the only way to do that these days is to have ones with OS maps in them. However, the OS charge extortionate license fees to map resellers. We can’t buy the rights from the OS to use our OS map data on any device. We must pay again and again and again to use our OS data on other GPS units. We fund OS to produce OS maps. They in turn charge us multiple times to use our data, that we paid them to produce. So GPS units can’t be sold as commodity items. They’re vendor locked mapping systems too expensive to duplicate. So you plump for the most advanced and hope it won’t go out of date any time soon. You just can’t afford to buy a spare.

If the OS changed their licensing terms to let us move our publicly funded OS data between GPS units, the new market created would become very competitive and providers would start to produce value added features that compliment our OS data, rather than being tied to the bottom line by the OS of just providing the data in the first place. We can basically say “here’s our OS data, what can you add it it and I’ll buy your device”. GPS units approach commodity prices and we can all carry a spare. Cue the navigation revolution. Smartphones are in the same boat. They’re in vogue at the moment until the market saturates when everyone buys one and finds out they’re now locked in to that particular vendor, via the application used to access their OS data on the move. So the heat’s been taken off the OS for a while but no doubt it will come back once people realise there is no way out of vendor lockin as long as the OS is charging for device based access to their data.

I think we’re on the verge of a revolution in navigation, if we can get GPS units, smartphone or otherwise down in price. But what about the “vi effect”?  The compass in the bottom of the sack but having no idea what to do with it. Why bother if you have three fully powered and configured graphical OS GPS units in your ‘sac?