British NW African Grid
Though not associated with WW1, I recently needed to research the map gridding system used by the Allies in Africa during WW2. Named the British North-West African Grid, it was not dissimilar to the gridding system used by the British Army and Royal Flying Corps / Royal Air Force on the Western Front. As I found it difficult to discover anything on the British NW African Grid, I thought it would be worthwhile adding the topic as a News item on my website. If anyone would like more information, please send me a message via the 'Contact' page
The map of Tunisia, for example, was overlaid with a grid of squares, each square measuring 1 Km x 1 Km (1 square km). Every 10,000 squares (a ’super’ square measuring 100 x 100 kms) was allocated a letter (once again, similar to the WW1 system) so that any location within an individual lettered area could be identified to an accuracy of 1000 metres. By dividing the sides of each 1 Km square into ten equal divisions, the accuracy of any location within a lettered area would then be improved to +/- 100 metres. With the grid reference for the centre of any lettered area being the same, viz. 500500, the Sheet Number or Letter identifier would be essential in pinpointing the exact location. So far so good.
It all got a little messy when it came down to making the military maps of Tunisia. Latitudinally was simple as each lettered square was divided into five maps (or sheets), with each map covering 20 km north/south - see below in the diagram I have created, overlaying the 90 Sheet numbers with their respective lettered ’super’ square. In their wisdom the British government wanted each map to be wider than its height, requiring each lettered area to be longitudinally divided into three maps, with each map covering 33 km west/east. Not only that, the lettered squares were offset so that the outer maps crossed over into the adjoining lettered area.
As an example I have attached the following images that show the location of map reference P 74 961 162