The series consists of seven glass negatives taken of aerial photographic survey print mosaics at a scale of two miles to one inch. The recording agency was responsible for geodesy; and, the medium and small scale topographical mapping of Australia for Commonwealth purposes. Geodesy is the branch of applied mathematics that determines the shape and area of large tracts of country, the exact position of geographical points, and the curvature, shape, and dimensions of the earth. Negatives of photographic print mosaics provided an additional check for the accuracy of aerial photographic surveys. After the aerial photographic survey film was developed the negatives were annotated with control information (e.g. individual photograph numbers, control points, flight information, etc) and given an initial check for accuracy (e.g. possible gaps in photography caused by camera failure, etc). The annotated negatives were printed and the prints laid out forming a mosaic. The mosaic (also known as a lay down) was checked to see whether any lateral gaps existed in the photography due to navigation failures during survey flights. The mosaic was then photographed, producing (in the instance of this series) glass negatives. If gaps were found the negatives of the print mosaics would be printed. Prints of the lay down would be sent to the operators who produced the aerial survey and used as reference guide to do a re-fly of the gaps. This system allowed for more accurate identification of gaps in the photography and minimised the amount of flights required to obtain complete coverage. In A2831 the mosaics take the form of contiguous strips rather than a fully fledged ‘photomap’ and the portions of mosaics that were not required were masked out. The series entered Archives custody without a registered system of arrangement and control. The series was controlled by Archives (based on information taken from the items) by sheet, run, and range of photograph numbers e.g. [A/WA-NT run/5048-5149] stands for sheet A of the Western Australia to Northern Territory run, photographs 5048 to 5149. Each item contains some or all of the follow: location, approximate scale in miles, approximate degree, scale for enlargement, date of creation, date of photography, sheet control (numerical or alphabetical), negative numbers (or range of numbers) of prints within the mosaic, and significant geographical features. Sources Series documentation Geoscience Australia, ‘Our History’, downloaded 5 May 2009 from http://www.ga.gov.au/about-us/history.jsp Geoscience Australia, ‘Aerial Photography’, downloaded 5 May 2009 from http://www.ga.gov.au/remote-sensing/aerial-photography/ Arctic Institute of North America's publications server, ‘Photographic Operations of the Royal Canadian Air force’, downloaded 29 June 2009 from http://pubs.aina.ucalgary.ca/arctic/Arctic3-3-150.pdf Arctic Institute of North America's publications server, ‘Photographic Operations of the Royal Canadian Air force’, downloaded 29 June 2009 U. S. Army Corps of Engineers Staff, American Society of Civil Engineers, ‘Photogrammetric mapping’, downloaded 25 June 2009 from http://books.google.com.au/books

Related series unregistered

International Index of Australia (Grid Map) Grid Index Cards to International Index of Australia