01-04-2016, 08:09 PM
Not sure even if that would have been in reference to an official map or a locally produced grid for the area. What may have been in use at the time was the Hayford ellipsoid. The Wikipedia entry for the newer European datum, ED 50, only says the following "Some of the important battles of World War II were fought on the borders of Germany, the Netherlands, Belgium and France, and the mapping of these countries had incompatible latitude and longitude positioning. This led to the setting up of ED50 as a consistent mapping datum for much of Western Europe." It would be interesting.