I would like to map a building (one from my University) and navigate through it using just the phone. No wifi/gps/bluetooth. I will give the coordinates of my starting position by taping the screen or something similar (I can also use the user feedback for detecting the floor).
What should I use to create the actual map of the building (floor map)? Could you give me some starting points/resources or describe how you would accomplish this task? I've got suggestions that I should use openGL https://www3.ntu.edu.sg/home/ehchua/programming/android/Android_3D.html Or maybe JOSM but I don't know if it can be ported to Android and used for mobile navigation afterwards.
Is there a simpler way? What should I use instead?
What would be the next steps after creating the map? Should I consider developing the code for navigation by myself? Any starting points here as well or similar projects?
Does the map need to be dynamic? If not, you could simply draw the floor map and display on the screen the image with your position on top.
Following your description I think the best solution would be using magnetic localization. Basically you would read Earth's magnetic field with the corresponding sensor and navigate the place with said data.
There are third party services that provide this kind of computation, like IndoorAtlas. You can use their android SDK and set up the navigation system by uploading a map of the building and running an initial mapping of the magnetic readings with your phone.