Wired: Four years ago, this column mentioned that amateur mapmakers were enthusiastically taking to the streets with GPS (global positioning system) gadgets. With the aid of these cheap, handheld satellite-driven locators, they could note their exact position, and tally together paths and road routes to create their own maps.
The "how" of that project is easy to spell out, especially now many regular users have our own GPS maps in our cars and phones. The "why" is a little trickier: why build your own maps, when ordnance survey maps are cheap and online mapping services such as Google Maps, Yahoo! Maps and Map24 are free to use?
Viscerally, it may just be because it's fun. It's the sort of pursuit that quickly moves from enthusiasm to addiction. It's a little like brewing your own beer or tinkering with your car. Driving around your local area, then beetling back to your PC to upload, annotate, tweak and share your homemade maps is fun, and watching your piecemeal contributions add to an increasingly detailed map of your area is strangely satisfying.
Like beer-brewing, it may be an enthusiasm that wanes for many, but for everyone who plays with the idea then fades away, a few new volunteers will replace them.
It has a political dimension too - or as close to politics as the usual reticent mapping geek will get. If you ask, the reason that would be given is "freedom". Using other people's maps requires asking for permission or, if you're using commercial sources directly, paying a licence fee.
That gets in the way of the usual advantages of doing stuff online: it's not so much the amount as the fact that such charges or requirements don't scale. If you have a few users for your ingenious mapping application, the cost may not be prohibitive. Become popular and you're suddenly obliged to turn a hobby or free service into a business.
If you want to, as many people do, give the whole caboodle away for anyone to use, you'll quickly come up short if you ask your country or corporate mapmakers to give you a blanket licence.
It's a parallel trend to the monetisation of the net, which you can see repeated again and again. Why start your own encyclopedia, when there is Britannica and Encarta? Well, partly, say the Wikipedia fans, because you can and because a free encyclopedia has many advantages and unique uses in a networked world.
I have Wikipedia on my phone and on my handheld PDA. A student in the developing world can access it, at no extra cost. If the world is missing a definitive definition of something I know something about, I can add it and Wikipedia (and my life) is just a little bit better.
Of course, because it is free, businesses across the world can take advantage of this new bit of knowledge infrastructure. The same is happening to the world of maps. The expensive mapping services of the Ordnance Survey are being worked around by enthusiastic, guerrilla cartographers.
The leading group in this area, at least in Europe, is the OpenStreetMap project. If you want to see how far it has got (and how far it has to go), you can visit their website but it's the discussions overheard from its recent conference State of the Map, in Manchester, that gives the best insight.
Its service now is a strange mish-mash of the perfectly accurate and the utterly blank. Dublin's map trails off before the M50; the map of the M4 is surrounded by pink nothingness for most of its route. It's not really usable for much; but hitting the edit tab on the website and adding your own corrections is addictive. A time-lapse movie of the growing map would be fascinating.
Like Wikipedia, these ragged-trousered cartographers are getting somewhere. In the UK, where OpenStreetMap began, the leaders of the project estimated they were 50 per cent of the way through and estimate reaching close to 100 per cent in the next year or two.
Like the state of Ireland's "openmap", half isn't quite good enough for everyday work but the switch from unusable to perfectly functionable is a short hop and has already been crossed in areas such as Oxford and parts of London.
Businesses are beginning to realise the advantages of supporting a project like this, too. Earlier this month, Automative Navigation Data, one of the leading Dutch providers of mapping data, donated an entire street database of the Netherlands to the project.
A British courier service provided several years' GPS logs of their couriers' movements across Britain.
At this rate, open or social maps will soon be competing with the traditional government and commercial databases, not for every use, but for a whole range of new uses that we have not been able to envisage.
Everyone benefits from these free projects but perhaps it's fair to say that those who profit most financially are those who study them early enough to base new business plans and models on what they are providing. Brittanica may be hurting from the rise of Wikipedia and Ordnance Survey and others may smart a little from the cockiness of these enthusiasts, but it will be the companies that recognise the new opportunities which will map out this brand new territory.
