score:9
There are many options for offline navigation on Android (tools that allow downloading maps and transforming your phone into a navigation assistant).
The other answers suggested MapFactor or CoPilot GPS.
There are another three free apps using openstreetmap data:
Upvote:2
Mappy GPS Free may help for offline navigation. In the French store, the app, the map of France and one French voice are all free. Other countries and voices can be purchased separately for a fee. From other stores, options, pricing and availability may be different... Map data is licenced from TomTom.
Upvote:3
Go for CoPilot GPS, it is free and it allows you to download maps to be able to use the app while offline, this is really useful when you are travelling and you do not have a data plan.
Upvote:5
I have used MapFactor, which was recommended to me on this site. It's free, uses the OpenStreetMap database (also free, with free updates) and is quite usable. You also pre-download maps so don't have to use 3G downloading as you drive around.
However if your GPS has country-specific maps for less than $20 I personally would opt for that. I find GPSes (or at least our GPS) easier to use for long trips than phones due to better battery life and their specifically designed software.
Upvote:6
You have a garmin gps. If it has support for a micro sd card you might be lucky. Open Street Map provides community contributed maps. it is possible to convert these maps to the Garmin image fill format and load it to your Garmin unit. To do this you need to be able to access the internal memory space of your GPS unit. I have a Garmin Vista HCx for quite some time now, which has a micro sd card slot and I now have a batch of micro sd cards with maps from all over the world. Whenever I go somewhere I simply slide the relevant sd-card into the unit and I am ready to explore. The recipe is relatively simple, you need to make the gmapsupp.img file containing the maps and load that file to your sd card under the Garmin folder. You can download precompiled gmapsupp.img files, or you can compose your own selection.
My GPS unit does not support voiced instructions, so I don't know how well this works with instructions. I have used my Garmin handheld unit in France though and I managed quite well. I have to admit that as an additional asset I do have the Michelin France maps on my iPad. I do miss the "helicopter-view" for oversight in a car navigation unit, so I like having access to digital maps on a iPad screen.