Thanks to Gordon Andreassend for explaining its history to me:
Aerial photography really falls into two categories:
- The use of a hand-held camera produces record photography, and consists of single shots.
- Aerial survey work requires a bigger camera mounted within the aircraft that is capable of taking a series of photographs that overlap by at least 50% (usually 60%). It is this overlap area that provides the cover required to obtain the stereo image.
The 1924 RAF photography was required for mapping, and was carried out as an aerial survey.
No further aerial survey photography was recorded until the 1963 survey for mapping was carried out by Huntings (a UK company).
Huntings returned once or twice in the 60's to capture more stereo photography, and it was not until 1968 that the HK Survey Office was able to carry out limited air survey work using an old air survey camera. That camera was lost in a plane crash in 1970, and in 1972, a new modern camera fitted in a twin-engined aircraft provided all the photography needed for the mapping of Hong Kong. The cameras have been upgraded over the years, but that aerial survey coverage exist to this day, and is handled by the SMO, using GFS aircraft.
All other photography from the air can only be considered as record photography, and we do know that such coverage was obtained by the RAF from 1924 until 1945, but was not recorded in Hong Kong.
Immediately after the war the RAF captured the record photography that is now held by the SMO. The RAF handed over all negatives they had at the time of the handover. The only complete record of this later RAF photography is that which the RAF took after about September 1945.
Gordon also explains his own involvement in this field:
After starting as a NZ-trained Land Surveyor, I worked in Australia and UK then came to HK on a 3 year contract in March 1966. HK was supposed to be a stepping stone back to NZ ! However, the work was interesting and 3 years became 30 ! I started work as an engineering surveyor, and as I had learnt to fly in Australia the boss thought I would be good to take on the job of flying in the Auxilliary Airforce on aerial survey.
At about the same tme I moved into the Survey Office to become the Cartographer - only one post at that time. The learning curve went up - and I signed on as permanent staff to move gradually up to the top slot of Govt. Land Surveyor, Head of the SMO, post now graded as Dep Director, Lands Dept.
Retired in 1995 - and still in HK !!
1930s Aerial Photography
There were aerial surveys done by both HMS Hermes and HMS Pegasus in 1931 and 1934 respectively.
Aerial Photography by H.M.S. Hermes in 1931
The surviving collection of Pegasus photographs in U.K. includes a loose note that several runs over Chinese Territory behind Mirs Bay were used for Sheet 4 of the Hong Kong 1/20,000. This note is assumed to relate to the 1931 survey referred to in the report of the Hong Kong Lands and Survey office : “Air photographs, taken in conjunction with H.M.S. Hermes, are being used for the revision of certain sheets of the 1/20,000 topographical map. The publication of which is now complete except for Sheet No. 4.
Aerial Photography by H.M.S. Eagle in 1934
In 1934 the GSGS reviewed the survey situation in Hong Kong with the aims of ensuring that, in the event of conflict, Hong Kong had,
a. A map printing capability.
b. Appropriate documented survey control.
c. Appropriate maps.
d. Appropriate artillery surveys.
It noted that:
a. The need for an in-colony print-capability to do operational overprints etc. had been negated by Hong Kong in 1932 due to the expense.
b. In 1928 the PWD had finally provided details of their field observations and the GSGS had carried out an adjustment of all the control, and produced a trig diagram and a list in geographicals and in China Grid with metre values. From then on this was referred to as the Primary Trig, albeit some positions were up to 4 or even 7 metres in doubt, and one, Castle Peak, of 12 metres. It was believed that the P.W.D. were still apparently using their own trig list, with many more stations than in the adjustment, with unadjusted trig values, using plane rectangular co-ordinates based on the Victoria Peak datum which might be different from that re-established by Wace!
c. The 1:20,000 scale map GSGS 3868 was probably adequate for artillery and defence purposes. d. There was a need for beacons, pickets, Observation Posts, the marking of conspicuous points, the marking of potential targets, Flash-spotting stations, Sound-ranging stations etc., all to be coordinated and marked and for appropriate trig lists to be available. It concluded that yet another survey might be required to meet the military requirement. In 1935, a detachment of Captain Newman R.E and five surveyors worked in Hong Kong on “defence requirements”, including revision of the 1:20,000 series. Also, new aerial photography was flown in 1934 and this photography is included in the surviving photo archive:
a. Hong Kong Island Mosaic. A letter from H.M.S. Eagle dated 15 Feb 1934 describes the two sets of photographs that have survived in the U.K. collection: “Eight runs of photos taken by aircraft from H.M.S. Eagle, A to H, of varying length were flown on a West-East track over Hong Kong Island between 1000 and 1200 hrs to give consistent shadow conditions at an altitude of 13,000 feet giving an approximate mean scale of 1:15,000.”
b. North Kowloon (The Gin Drinkers Line) Two sets of photography have survived of an area 9 x 3 miles in extent of the hills north of Kowloon between Gin Drinkers Bay and Port Shelter. Six runs of photos, taken by aircraft of H.M.S. Eagle, runs A-E and X, were flown on a West-East track.
c. Shing Mun Reservoir Area. Five runs of about 10 photos were flown on a North-South track over the Shing Mun reservoir area, reportedly with a 10 ¼ inch focal length camera by aircraft from H.M.S. Eagle. The contact photos are 5 x 5 ins format, hence probably taken with an F24 camera.
I assume the surviving photographs can be found here, however they are not online. It is possible to do a paid image search but it is not cheap. It is also possible that the photos are in the National Archive here
I also recommend reading the full document from where the above information was sourced for a very interesting read on pre WW2 military mapping in Hong Kong. I assume the author MA Nolan is the same Mike Nolan credited for the maps here. David do you know Mike Nolan at all?
Full Document The Cruise of the Pegasus and GSGS 3868
Early Aerial Photos
If you are interested in old aerial photos of Hong Kong, the National Collection of Aerial Photography has nearly 2000 images of the territory, inluding hundreds of images from the 1924, 1934 and 1964 aerial survey of the territory.
http://ncap.org.uk/news/hong-kong-aerial-images-released
The images can be found at:
http://ncap.org.uk/search/keywords/Hong%2BKong?free-text=yes#free-text=…
You can veiw and download each image but if you wish to zoom you need to register.
Enjoy
The Cruise of the Pegasus and GSGS 3868
Great my password is OK ! Thanks.
----------------------------------------------------------------------------------------------------------------
I have only recently read this paper by Lt Col M.A. Nolan (ret'd), and found it most interesting. I knew Mike Nolan during his time in Hong Kong, as he was the head of the Military Survey establishment in Hong Kong for about 6 or 7 years prior to their 1997 departure. We liaised on map production for their military requirements, as the military ceased to print coloured topographical maps in the late 1960s following the Departure of UK military forces from Singapore, where their map production unit for the Far East was based. The situation was reversed, as the military used maps produced by the Survey and Mapping Office, and overprinted their military information, from the the early 1970s until 1997.
As it was, I had only just been appointed to the post of Cartographer in 1968, a new post in the Crown Lands and Survey Office, when the the Colonel in the Military Survey unit visited me to inform me that they would no longer be able to supply us with coloured topographical maps. The head of the Survey Office, John Cooper, told me to select staff for training overseas in map production, and things went ahead very quickly to the point where our office took over the production of all the coloured maps for Hong Kong. The cartographic staff was expanded rapidly, and excellent results were achieved, as in very little time the office was receiving overseas awards for the standard and quality of several Hong Kong map products.
JerkJi