Get yourself a clip.
If youŽre wearing an overall-there should be a pocket or pen pocket on your left leg....slide the clip in-itŽll hold the map.
If youŽre flying in jeans-get yourself a strap.
YouŽll find them in any Aviation Shop that sells pilots equipment....
The strap wraps around your leg-slide the clip (or even a pen or a pocket knife with a clip) under the strap-there you have your map holder!