Tuesday 8 December 2015

Mapping Jordan

Quite recently John Bartlett published a marvellous survey of Mapping Jordan through Two Millennia, London (Maney for PEF, 2008). Until the First World War all mapping had been terrestrial. Much was based on compass bearings and estimates of distance derived from travel time. As such there was progress but often still very inaccurate. Some of it was linear and reminiscent of the similar routes in the Roman map known as the Tabula Peutingeriana.

Major developments came in 1867 and – in particular, 1881 when the two expeditions sponsored by the Palestine Exploration Fund saw teams drawn from Britain’s Royal Engineers at work ‘east of Jordan’. The expedition led by Lt. Conder in 1881 had previously mapped extensively in ‘Western Palestine’. Now the grid was carried to ‘Eastern Palestine’ and places in north-western Jordan were carefully located by a sophisticated triangulation survey.

The next major development in mapping techniques and in increasing precision, was a by-product of war. All the protagonists on the ‘Palestine Front’ were in desperate need of reliable maps of both the wider area and specific sections of the Front. Much of the work of aerial photography for intelligence purposes and mapping was delegated to the sole Australian Squadron amongst the British Imperial air forces. No. 1 Squadron AFC was also sent across the R. Jordan to photograph specific places and bring back vertical and overlapping aerial photos of key features such as the major roads and the Hedjaz Railway line.

The British expeditions across the Jordan to attack the Turkish administration centre at Es-Salt and to Amman to cut the railway and block Turkish forces retreating northwards from Arabia and southern Jordan  took place in March, April-May and September 1918. There is no surprise that the Royal Engineers were soon preparing maps of the region between the R. Jordan and the Hedjaz Railway.

Three editions were published of each of two sheets – one for Es-Salt and one for Amman. Copies are held at The National Archive in London and in the State Library of New South Wales in Australia – and doubtless other places.

Rubric from 'Composite Map East of Jordan (Amman) 2nd. Edition' - "...detail overprinted in purple is from photographs taken by the R.A.F. ...", the first known use of aerial photographs in mapping Jordan.

What makes these sheets significant is that for the first time for Jordan, aerial photographs were utilized. Specifically, the 2nd editions of both the Amman and Es-Salt sheets have a rubric saying that the map was originally published on 22 April at which time they had already inserted some information from ‘RAF aeroplane photographs’ onto maps based on that originally made by Conder’s survey of 1881. Both sheets then have printed in purple: “The detail overprinted in purple is from photographs taken by the R.A.F. 7th Field Survey Coy. R.E., G.H.Q. E.E.F. 26th April 1918”. (27th April in the case of the Es-Salt sheet).

This is the first known use of aerial photographs for mapping in Jordan. It seems to follow on from the second abortive ‘raid’ east of the R. Jordan and may reflect the need for improved maps before the third – successful, expedition. Both sheets represent the use of aerial photos for Jordan which predates the use by the Germans on some of their maps of the same region – the German Salt sheet of 5 August 1918 has a rubric reading: erg√§nzt nach eigenen Messungen und nach Luftbildern der Feldflieger Abt(eilung) (“supplemented from our own measurements and from aerial photographs of the Field Aviation Unit”).

Once begun in 1918 the use of aerial photos for mapping was soon to become the most cost-effective and accurate method for Jordan and for everywhere else.

No comments:

Post a Comment

Note: only a member of this blog may post a comment.