Page 79 - Ranger Demo

the Programmes were amended. It was found that photos taken early in the morning or late in the afternoon were not successful for CB work as the pits were filled with shadow, and it could not be seen whether they were occupied or not.
Separate copies of the photos were not available for CB owing to lack of printing facilities. The CBO at Wing HQ got possession of the photos after the AAPIU (Army Air Photo Interpretation Unit) had finished with them. Immediately before and during the offensive special arrangements were made and a separate copy was made available. It is most desirable that this should always be so. At the start, co-ordinates were obtained by the mosaic method, the accuracy of which varied from “W” to “C” according to the distance from control points. On completion of the Block Plot by RE Survey Coy., (which entailed taking special runs to link the plot together), (see para 2) co-ordinates of all HBs could be found to within 50 metres. In many cases locations obtained by FS and SR agreed within 10 or 15 metres – none differed by more than 30 metres.
To obtain sufficient control points to make the Block Plot accurate, photos had to be sent forward to the Survey Battery who identified points in our own FDLs (forward defence lines) and surveyed them in. It is obviously desirable that these plots should be made in advance for all areas where the enemy might make a stand. One was, in fact, prepared for Bardia in case the enemy had tried to hold it. The RE Survey is hampered in this work, however, by having to work off ordinary photos which are tilted. Planes for Survey work are extremely few, so that verticals cannot be obtained when required. This Plot being the only means of obtaining really accurate co-ordinates in the desert is extremely useful for purposes other than CB.
A large-scale map of the enemy defences was made from it upon which most of the barrage for our offensive was based. The CB Office also provided the local gunners with much air photo information such as co-ordinates of strong points, minefields, wire, infantry posts etc. Where photos covered our own lines, Regiments were invited to see the photos of their own gun positions to observe the effect of their camouflage. Apart from its intrinsic value this passing of information enabled many personal contacts to be made with consequently better liaison and co-operation. It is doubtful if the enemy fully realizes the extent and frequency with which it is photographed, or the uses to which the photos are put. Many of his methods of “foxing” CB were rendered abortive by our air photos. (See para 9 (b) (iii))
Ground Ops etc
The degree of co-operation from Artillery Regiments, throughout the front was excellent. Information from Ops was complete and sent in quickly. The time for Shelling Reports to reach the CBO naturally varied with individual Regiments and the communications available, but where communications were good, some Regiments consistently got Shelling Reports into the CB Office three or four minutes after origination at the OP. The average time was about ten minutes. The advantage to the CBO of this speed cannot be overstressed and emphasizes the necessity of ........................................ Etc.
Extracts transcribed from TNA WO 201/2821
77