OruxMaps is a comprehensive mapping and GPS application that also
happens to be completely free, although if you use it a lot the author
asks you to donate to help fund its development. The app is designed to
act as a complete replacement for a traditional handheld GPS receiver.
It allows you to use downloaded maps as well as online maps, so you
don’t always have to have a net connection available in order to
pin-point your location.
Read the full OruxMaps Android App review