How were the aerial photographs taken?
The 1170 frames taken in the winter of 1943 offer a complete picture of the city and much of the surrounding areas. The aircraft flew 37 mainly east-west, straight line runs (such as from Smithfield to Watsons Bay) at around 2600 metres, taking about 45 separate photographs in each run. Each photo overlapped the previous by approximately 60 per cent. On the return run (such as from Vaucluse to Canley Heights) the photography overlapped the adjacent run’s coverage by about 30 per cent.
The camera (probably a Fairchild reconnaissance camera) produced large negatives - 164 mm by 222 mm - and recorded on each negative were the frame number, time, date and the altitude of each exposure.
An instrument called an “intervalometer” was used to allow the camera to accurately register the frames. Today, a global positioning system (GPS) is used in conjunction with a computer which calculates the average height of the terrain and how often it has to fire the camera shutter.
While modern technology has resulted in more accurate cameras and lenses, the quality of the black and white images is excellent for the 1940s.
The aerial photographs were painstakingly preserved by Roads and Maritime Services (replacing Roads and Traffic Authority) as a part of Sydney’s heritage.
When did aerial photography commence in Sydney?
The first aerial photography of parts of greater Sydney was undertaken in the late 1920s by Federal agencies such as the Defence Department. It appears that the 1943 photographs were the first taken for the purposes of road planning.
Aerial photography of Sydney is undertaken at various photo scales on a regular basis. Its main purpose for Roads and Maritime Services (RMS) is to link with on-ground surveying to determine the location of new roads and to guide the improvement of existing roads. Today, aerial photography is done mainly by commercial companies who make the images available for different uses. The photographs from 2000-2004 were kindly provided by Sinclair Knight Merz Pty. Ltd. which has contracted aerial photography in more recent years.
Can I purchase an individual aerial photograph?
RMS cannot provide individual aerial photographs other than the posters of the 10 areas.