Open Sauce (and how to get there)…

OK, so I’ve blogged about it before, but I wanted to talk about an Open Source development called OpenStreetMap. This is an Open software development using user generated mapping information to generate GIS data. 

So why the need for this, when TomTom, Google Earth et al all do an excellent job of providing mapping information.  Well, the simple reason is that companies own the copyright to their mapping data and information, meaning that if you want to use it, you have to pay a (some times hefty) licence for the privilege.  Alternatively, you COULD rip the information off one of these providers, but the chances are you’ll get caught.  Even a respected company like the AA has fallen into this trap, copying Ordinance Survey maps and reselling them as their own work.  You would think that a map is a map and its impossible to tell what's been copied, but mapping companies are clever – they add subtle details into maps which won’t affect their day to day use, but act as markers to highlight plagiarists. For example, they’ll add a small fake road at the end of a street, where only terrace houses exist.  Or, they’ll add a kink in a road that doesn’t exist – it doesn’t affect the general use, but unless you go there and map the information yourself, you’d never know it wasn’t really like that.

So OpenStreetMap is designed to be the wikipedia of maps – people go out into their community, collect mapping data (using GPS logs, photo’s and notes) and then converting this into a digital map available to the community under a creative commons licence.  The process of generating a map is

1) Go out and get the data – Use a GPS to log your position, make notes of street names,  any points of interest along the way (such as pubs, post boxes and the like) and perhaps even photo’s of the area.

2) Map the data – Import your GPS track logs,  convert this into mapping data such as streets, street names, speed limits and the like.

3) Publish your work – Send the data to the OpenStreetMap server for use in the map.

If you visit www.openstreetmap.org and have a look around, you’ll notice that many Urban area’s of the UK are reasonably well mapped.  This is the case of my local area, apart from the side streets in my neighbourhood.  I’ve already added a couple of streets to see how reasonably easy it is, and now I’ve got the bug to start gathering and updating more data.  One useful feature of the service being opened is that you can make changes where you spot a mistake on the map – so for example, if you spot a speed limit has changed, whilst it might take TomTom 18months+ to update the map,  you can make the change there and then, and then that will be available to all.  Id highly recommend anyone with a GIS, mapping, geographical or community interest to get involved and expand the quality of the data – why not have a mapping party and get loads of people involved – all you need is a GPS logging device (many phones are now capable of this), somewhere to record notes, and a bit of patience actually map your area.