This is the TopoDroid app (com.topodroid.TDX) repository.
TopoDroid is a productivity Android app for cave surveying. It is specially designed to do cave surveying with the DistoX, although it can be profitably used even without it.
Visit the website https://sites.google.com/site/speleoapps for more informations about TopoDroid, and in particular for the version changes doc.
All the code is provided under GNU General Public Licence v. 3