WWI Trench Maps & Aerial Photographs
Specialty Maps: "Positions"
Beginning in 1916 "Positions" maps were created in order to show all enemy battery positions located by aerial photography, flash spotting, sound ranging, kite/balloon, etc.
The image below is taken from a map in our collection (ID #339ww1map).
image of a "positions" map

Contact: mapref@mcmaster.ca