David Earl is a member of Cambridge Cycling Campaign. He cycled every street in Cambridge and surrounding villages to make the Cambridge part of OpenStreetMap one of the best mapped areas in the UK. Earl's work was used by Cyclestreets of Cambridge to help perfect a local map routing engine that later went national.
OpenStreetMap is getting more and more detailed over time, but some places are better mapped than others. Earl wants other cyclists to 'fill in the gaps', and no mapping experience is necessary.
"Map data is collected by volunteers. A bike is the perfect tool for gathering it," said Earl.
"Anyone can contribute to OSM. Why don't we just use Google maps? They are just pictures of the street pattern. To work out routes we need a connected model of the streets. Why not Ordnance Survey? Until 2010 it was prohibitively expensive. Even though a lot of OS data has now been made free, like Google maps it also doesn't have a lot of the detail that's important to cyclists and cycle routes. Nevertheless OS is a new source of some data for OSM in the UK.
"But there's no real substitute for getting out there and gathering the data on the ground."
For keens, Earl recommends use a GPS.
"If you're in a sparsely mapped area, you'll need a GPS receiver, one that can be connected to a computer to get the record of where you've been. Then you need something to take notes of street names and features. A pen and paper will do but a digital voice recorder is especially good on a bike because you don't have to stop and start.
"ecord what you see. If you can survey an area systematically so much the better. For best cycle routing the really important things are the types of road, any cycle facilities, any restrictions like one way streets and no right turns, and exceptions for cyclists. Local knowledge of short cuts accessible by bike are often not recorded on conventional maps.
"Where a skeleton of roads already exists, we need to augment it with missing streets and particularly the extra information on cycle facilities and restrictions. You don't necessarily need a GPS to do this. You can reference it to the existing map. An excellent tool called Walking Papers helps doing this."
You don't have to be a map geek to help out.Simple corrections to the map can be notified very easily through the OpenStreetBugs website. Someone else will make the change for you.
Once you've got your data there's a number of tools to let you add it to the map. This usually takes about the same time as collecting it in the first place, at least for urban areas. There is a map editor on the OSM website (click on the Edit tab) and the new Potlatch 2 editor which is more user-friendly. There are also other editors, JOSM and Cloudmade, for example.
"The most important thing in editing the map is to make sure all your streets join up," said Earl.
"It isn't enough that they just look like they join - the route calculations can't then move from one street to another."
The OSM website has a step-by-step beginner's guide.
"There are mailing lists, blogs, chat forums and so on where lots of real people will be very willing to help you. Part of the joy of a project like this is the community of like minded people behind it. Many of them are also cyclists," said Earl.
"Finally you have the satisfaction of seeing your work appear on the various maps, usually within a few minutes."
OpenStreetMap is refreshed frequently and this mapping is used on OpenCycleMap, which is what powers satnav apps such as the ones from Bike Hub and CycleStreets.
Bike shops which want to add new store locations can use this self-help guide.