This Android app displays images that represent maps. To be useful the maps must have an associated calibration file that assigns the latitude and longitude for the pixels of the map. (The Help describes ways to create this file.) The device's current location can then be displayed in Map Image, showing where the user is on the map.
The images can be very large as they are implemented by tiles.
The app does not use a data connection and so can be used in locations where there is no connection, such as out in the woods. It also does not run up data charges.
More information and FAQ are at https://kennethevans.github.io as well as more projects from the same author.
Licensed under the MIT license. (See: https://en.wikipedia.org/wiki/MIT_License)