Ralf, that is exactly what I'm talking about. Below are a couple of test images:

I used a simple and cheap Garmin GPS, running a track log in my pocket while I took photos facing mostly down and a little forward as I walked across a large horizontal petroglyph site. Later, I synced the photographs to the GPS track log and exported out new JPGs with latitude and longitude EXIF headers.

That allowed me to generate an oriented model with a darn good scale.

close-up

I need to map a giant area in this fashion. The resolution of my UAVs cameras' isn't high enough to get the detail required. The example above is only two transects and a test of the concept. Promising...
-Mark