Is it possible to write offline GPS navigation software as a hobbyist?

Question

Basically I'm wanting to create a GPS system for my car that works offline, but I'm just a hobbyist and doing this for fun, so I don't have a ton of money to invest. Are there open databases I can use for the data (roads, speed limits, etc), or is it just impossible to do?

Answer 1

There's http://www.openstreetmap.org/, which aims to be a free mapping database. It is far from complete, but as a starting point it might fit. Look at their wiki: http://wiki.openstreetmap.org/wiki/Main_Page

Answer 2

OpenStreetMap is an attempt to create a Creative Commons street mapping database. More info can be found at http://en.wikipedia.org/wiki/OpenStreetMap and http://wiki.openstreetmap.org/wiki/Main_Page

OSM is actually the basis for one of the iPhone navigation apps called Roadee, more info on their site at http://www.roadee.net/en/ - it's very cheap so if you have an iPhone you could install that to give you an idea of the data limitations (lack of 6 digit postcode search is one limitiation I know of off the top of my head).

Answer 3

The Tiger database from the Census Bureau might be of interest. I've used this for my GPS hobby applications. It doesn't have the data you need to calculate driving directions or find speed limits, but it has the data you need to draw maps.