Wednesday, November 9, 2011

British Aerial Photography and Photographic Interpretation on the Western Front - Pt 18

Back to Part 17

The Uses for Aerial Photography

Foundation Material

During the retreat from Mons in 1914 the scale of the movement involved meant that there was no requirement for detailed large scale maps to support the BEF.  The first demand for large scale detailed mapping came after the battle of the Aisne as the front line began to stabilise.  At this time with no trained surveyors available the BEF had to make do with the inaccurate 1:80,000 French mapping enlarged and redrawn at the Ordnance Survey Office Southampton.  These enlargements were completely unsatisfactory, reproducing and magnifying the errors on the original that introduced gross positional errors.  What was needed was a new field survey of the BEF operational area.  In November 1914 two trained surveyors arrived in France as part of the First Ranging Section RE’s.  These two surveyors were tasked with completing a survey that would enable a more accurate map to be produced in as short a time as possible.  Their field work started on the 25 January 1915 and by the 28 February all the field sheets were passed to the Ordnance Survey for reproduction.  The resulting 1:20,000 scale map was a vast improvement on the previous 1:80,000 enlargement (Winterbotham, Survey on the Western Front. pp. 6-7.).  Its comparative accuracy improved the targeting accuracy of the British artillery and led to demands for accurate mapping of the German held territory.

As mentioned previously, the responsibility for mapping the German-held territory rested with the GS Intelligence. However, the success of the Neuve Chapelle battle map ultimately led to the formation of Army Topographical Sections that became responsible for all map production in their Army’s area of interest.  By the end of 1915 a newly created series of 1:10,000 base map sheets overprinted with the tactical detail of the German defensive positions had been produced.  Aerial photography was the primary source used to derive both the topographical and intelligence detail displayed on the mapping.

Figure 8.  Extract from 1:10,000 scale trench map produced in 1916.

Illustrated above (Figure 8) is a section of the standard British 1:10,000 scale trench map overprinted in red with the German defensive positions.  From 1916 maps of this type would be found adorning the walls in HQ’s and Intelligence sections throughout the BEF.  The BEF now had a coherent framework on which to build a COP.  The real challenge was to maintain the pictures currency to ensure a high level of situational awareness at all levels of the BEF.

Next: Part 19 ‘Situation Awareness

No comments:

Post a Comment