Set out below are links to original GSGS maps of the time, which can be used in conjunction with the map references given in the war diaries to pinpoint original locations on the ground. The list is not exhaustive but the main areas are covered, particularly in Holland, and further maps will be added as and when they are identified. The maps are mostly held by the British Library, McMaster University in Canada and the Library of Congress in the US.
Other websites providing original maps include:
National Library of Scotland: http://geo.nls.uk/maps/belgium/gsgs4040/googlemaps.html
Locations can be transposed onto modern-day maps (Google Maps/Earth, for instance) with a reasonable degree of accuracy by calculating the positions relative to salient features that are unlikely to have changed a great deal since the war (such as old roads, rivers, canals, churches, etc). Instructions for plotting 4, 6 and 8-figure grid references can be found online.
This original map of the TURNHOUT-GHEEL area in Belgium is from the war diary of the 9th Cameronians and, along with the mud, shows the detailed locations of the battalion’s companies during the fighting at Gheel between 12 and 20 September 1944.