There is quite a number of formats out there. I was actively looking into all of this stuff before getting laid off. Autodesk for example, supports a mapping format. Many of the mapping formats are "open" in the sense that development is encouraged but in almost all cases the data itself is never to be redistributed. You *can* get map data for free from the government. For example, California State DOT will release data in various formats, and I believe you can get Tiger data for free as well. The problem is accuracy. The DOT map data looks like ass for everything except for the major highways for example. Companies like NavTech base their original maps on government data, supplement that with recent satellite data, then they employ hundreds to thousands of drivers carrying GPS units manually probing the nation's roads constantly in order to verify the data. This cost overhead is what you're paying for. If they give away the data for free they will go out of business and the quality goes way down.

Calvin