Navfree USA is a North American localization of worldwide, crowdsourced and open-sourced GPS navigation software that is offered for free in the Android market. The world version of the app supports navigation in about 34 countries. Navfree USA chooses to focus on the 50 U.S. states, Canada, and Mexico.
There are two reasons someone would want to take a look at Navfree. Firstly, it's free. There are no charges for map downloads, updates, voices, or language packs. Secondly, the free maps are downloaded and stored locally, which means that you won't have to ping a server to download map tiles while on the road or to calculate and recalculate routes. There's also a third reason to consider and that's the warm and fuzzy feeling that you get when supporting open-source software -- if you're into that sort of thing.
Locally stored map data
After installing the app, the first thing that you'll want to do is to pop into the Upgrades section of the main menu to download the map data that Navfree will need for navigation. If you speak a language other than English or would simply like a different voice for your turn-by-turn directions, here's where you can download additional speech packs, as well.
The map data is provided by OpenStreetMap.org, an open-source repository for crowdsourced and community-moderated street map data. Think of it as a decentralized version of Waze or TomTom MapShare or like Wikipedia for road maps.
OpenStreetMap.org maps for the state of California took up 248.7MB of storage space on my device, so you'll probably want to make this download over a Wi-Fi connection. Factor in the space taken up by the app itself and the total storage footprint for Navfree USA on my Google Nexus 7 totaled up to 314MB, which isn't too bad in the grand scheme of things. However, by comparison, CoPilot GPS' maps for the entire Southwest United States (covering Arizona, California, Nevada, New Mexico, and Utah) only took up 172.6MB, with a total app storage footprint of 207.8MB. Now, it's difficult for one person to compare the accuracy of all of that map data, but CoPilot manages to squeeze in four more states with 100MB less data. If you're looking for the absolute smallest footprint on your SD card or internal storage, this is important information to know.
Like most crowdsourced data, the OpenStreetMaps are constantly being refreshed, revised, and (hopefully) improved. So, you'll want to periodically check the app's Upgrades screen for updates. I received two full map updates during my two weeks of testing.