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.
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April at which time they had already inserted some information from ‘RAF aeroplane photographs’ onto maps based on that originally made by Conder’s survey of 1881.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: ergänzt 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.