What is the license, how can I use it?
The OpenStreetMap Geodata License
The OpenStreetMap project provides increasingly extensive map data for the entire world that you can download and use for ANY purpose you like.
Usage of the geodata is controlled by a license. The most important thing about the license is that you do not have to pay anybody anything to use the data. There are NO copyright, license, usage or other fees. You may use the data for personal, community, educational, commercial, government or any other use that you can think of. We, the OpenStreetMap community, ask only two things in return.
Firstly, that you attribute OpenStreetMap, i.e. you show clearly where you got the data from. A lot of contributors have spent and spend a lot of time and effort adding data from virtually every country in the world. We would also like people to know about our project and perhaps use or contribute data themselves.
Secondly, you "Share Alike". If you publicly distribute something that you have made from our data, such as a map or another database, and you have added to or enhanced our data, then we want you to make those additions publicly available. We obviously prefer it if you added the data straight back to our database, but you do not have to, as long as the public can easily get a copy of what you have done. If you do not publicly distribute anything, then you do not have to share anything.
Our current license is called ["CC-BY-SA", the Creative Commons Attribution Share-Alike version 2.0. Here is [readable summary] and here is [the full text].
We are currently changing the license, read more about it here. If fully accepted by our community, data will be re-licensed under the Open Data Commons
Both licenses are broadly the same, you can use the data without payment, provided that you "Attribute" and "Share Alike". However, the new license is specifically written for databases. It offers our project more protection. Attribution is more practical. It is a lot clearer on when "Share Alike" is triggered. It also always you to make maps with layers from different data with incompatible licenses. In short, we want even more people to use our data.
Is it really free?