Public data for OpenStreetMap

In recent months, growing recognition for OpenStreetMap has led to an explosion in imports of public and private data. Mapping every street, lake, skiing piste and pizza takeaway in the world might sound like a fun hobby, but being able to pull in your government's basic street network makes the job a whole lot easier. This mix of "crowd sourced" map data from volunteer efforts, private and public donations of data, and commercial developments based on the results, is a classic open source story.

OpenStreetMap was founded by Steve Coast in 2004, borne of a frustration with the prevailing preference for proprietary data in the UK. The Ordnance Survey, which can trace its roots back to 1747, is the part-government funded agency with some of the world's most detailed and best loved maps. Unfortunately they charge you an arm and a leg to get the underlying vector data. So out stepped Coast, equipped with a GPS, notepad and pen, followed by tens of thousands of volunteers all manually gathering the data to enter into OpenStreetMap's database. To get a feel for the explosion of data over the past year, look at this great video.

Thankfully, help for the crowd was at hand from the start. Coast quickly secured an import of GPS traces from a courier company for central London; the donation cost the courier company nothing but was very helpful for OpenStreetMap. Much more impressive imports began more recently, with the US census bureau's TIGER database bringing data for the entire street network for the United States of America in late 2007. The Netherlands appeared in even finer detail around the same time, thanks to a donation by Dutch company AND.

This process has now rapidly accelerated. You can get an idea of the scale of the import activity from these incomplete wiki pages on importing government data, the catalogue of major imports and the enormous list of potential data sources. These imports vary from quite comprehensive -- such as the Canadian Geobase -- to very specific datasets like NAPTAN (UK public transport access points) and UK oil wells. Importing vectors for buildings in addition to roads has been popular, examples include Boston in the USA and Naga City in the Philippines.

Of course, most of these imports have come from governments and public agencies who are empowered or required to release the data into the public domain. Any import needs to be carefully reviewed to ensure that copyrights - and database rights in Europe - aren't infringed. For those of us mapping in countries like the UK, this means more walking and cycling, with only occasional negotiations opening up niche data such as oil wells and bus stops. Politics still holds the project back -- or makes for more fun, depending on your perspective.

Politics was a driving force behind one of the most interesting recent collaborations between volunteers and public / non-governmental agencies. Whilst the world was watching the Israel-Palestine conflict on TV, long-time OpenStreetMap volunteer and geospatial activist Mikel Maron was attempting to produce high quality maps of the Gaza strip. Maron worked with UN and aid agencies to obtain data, gain the funds to buy aerial imagery that volunteers could trace, and locate Palestinian expatriates who could fill in details from memory.

With commercial uses for OpenStreetMap emerging, such as the recently unveiled CloudMade developer products, and free software projects like Marble integrating the maps into their interfaces, OpenStreetMap is gaining clout. In the country that started it all, a government-commissioned study found that there would be more economic benefits for the UK if map data was released into the public domain than under the current proprietary model. Under pressure from a growing campaign, and these compelling examples of the benefits of open collaboration, we might just see the terrain shifting from a few interesting imports to a major change in mainstream attitudes towards public data.

At the very least, you'll have a lot of high quality map data to play with at your leisure in the future.

(Interested in adding data to OpenStreetMap? Tom Chance will be returning in the near future with a look at how that process works.)