I’ve heard about OpenStreetMap (OSM) (see the Wikipedia article) maybe one or two years ago and was interested in the collaborative aspects of it. This mapping project aimed to create a free (as beer and in speech) street geodata of the whole United Kingdom and Ireland. While Great Britain already has excellent mapping data care of the Ordnance Survey (the national mapping agency of the UK), the problem is that this data is not free (as in beer and speech). The Ordnance Survey holds the copyright to the mapping data and charges people who want to use it, despite being funded by taxpayer’s money. So the OpenStreetMap project was born.

OpenStreetMap builds street data primarily by using Global Positioning System (GPS) tools and equipment. The GPS “tracks” are then collected, thrown into a database, annotated, and then rendered to produce street maps. This way the data is truly free of any pre-existing copyrights and is released under the Creative Commons Attribution, Share-Alike 2.0 license.

I haven’t been following developments on OpenStreetMap, since they only did UK, but when I recently checked them out again, I was surprised to see that they’ve expanded the project to cover the whole world. There’s already some data for the Philippines, mostly concentrated in the Metro Manila area. There’s even a Philippines page for contributors.

One interesting development on OpenStreetMaps that I missed was that Yahoo! agreed to let the OSM use its satellite imagery data, derive data from it, and release the derived data for “free,” without having to credit Yahoo! (See the OSM Wiki page about the arrangement.) This greatly simplifies the mapping process because before, you needed to use GPS to get copyright-free street data, or else use low-resolution LANDSAT satellite pictures, or public-domain but outdated maps. Now, you don’t need to have a Nokia N95 or other GPS units to get data; just load the Yahoo! satellite image, trace the roads and presto! Instant vector maps! Check out the “Edit” tab in the OSM website (registration needed).

This is great news for us Filipinos because Yahoo! already has satellite imagery of Metro Manila and Davao City. Migs Paraz has been ranting about the lack of nice Metro Manila street data (mapCentral, while it has the best map data of the Philippines online, is not very user friendly), so he might be interested to check OSM out. When I have time, I’m definitely going to map out my neck of the woods.

P.S. I’ve been meaning to write about OSM since last week, but this post by Abe catalyzed me to do it.

Update, August 6. Based on feedback, I’d like to clarify some of the points and give more background. I have exaggerated when I said that it’s easy to create street maps by just tracing satellite images. Any data you extract based on satellite imagery should be cross-referenced and corroborated with other sources of information such as personal observations, ground-level photos, other maps, etc. So, the best person to create street maps from satellite images is the one who is knowledgeable about the place. You can’t expect me to create street maps for Sydney, for instance, but you can bet that I can create maps of the Makati Central Business District. More discussion can be found at talksmart’s reaction and the comments that follow that reaction.

The reason I checked out OSM was because of this article on the Google Earth Blog: “India Maps - Local Knowledge Power”. This is the same topic that Abe discussed in his blog post that I linked above.