Some people might not see the reason for a project like OpenStreetMap when there are plenty of good mapping products and services laying around. I am not one of them. Whenever I use a GPS, I think quite a bit about it’s inner workings. How does it figure out which route is best? How does it calculate things on the fly? All of these questions usually lead me to think, at one point or another, that it depends very much on the data. While most mapping services and individual GPS devices use various algorithms for calculating routes, etc. (prob based on some weighted graph or something), they also rely on different sets of map data. A GPS can only tell you where on the planet you are, not what road you are on. For that, it needs map data. The only issue is that all of the map data used by popular services is proprietary! Enter, OpenStreetMap. Seeded with the geographical data made publicly available by various governments and public universities, OpenStreetMap provides Free (as in freedom, licensed under CC-BY-SA) map data to anyone who wants it. The data is usually in pretty good shape because the initial measurements are in good shape. However, things aren’t perfect. Lucky for the web, OpenStreetMap.org allows users to help improve the data in a number of ways. First, users can upload GPS traces to help improve the quality of unmapped regions such as seriously-rural areas along with bike and hiking trails. Second, users are able to tweak the mapping data to correct errors. There are a number of ways to do this but OpenStreetMap.org has an online editor which lets you overlay OSM data onto sattelite imagery so you can move those roads, landmarks and the like into the right location. In about an hour, I had cleaned up much of my hometown and began to add local landmarks, parks and buildings. It’s quite easy. The project itself seems off to a great start and the planet shows a fair bit of activity. In particular, I like the idea of mapping parties where people get together and work on a given area. This seems like a great way to give back to the community and I plan to float the idea at the next SCOSUG meeting.