Historical information
Orthophoto mapping provided the Survey Corps with the capability to produce map products quickly in the event of a crisis. These are four photographs of equipment used by the Army Survey Regiment to produce orthophotomaps. The Wild GZ1 orthophoto projector shown in photo.1P was introduced in 1973 and was the first equipment used to orthorectify colour and monochrome film aerial photography. Height profiles were originally produced on a PEB8 Stereo profiler and later were software generated. Photos of the PEB8 are available in Victorian Collections item 6222.17P, photos .5P and .6P. In the same era the IBM 1130 computer; OMI/Nistri AP/C-3 analytical plotter with coordinatograph, OP/C orthophoto projector and Zeiss Planimat D2 stereoplotters were introduced. Orthorectification is the process of removing geometric distortions and scale errors/variations from images. Images have tilt and relief distortions that make it difficult to compare accurately a map and an image of the same geographic area. Once an image is orthorectified, features on the image are shown in their planimetric locations. The WILD OR1 orthophoto projector and workstation shown in photos .2P to.4P was introduced in the mid-1980s. It was the second-generation equipment used to orthorectify colour and monochrome film aerial photography, replacing the system introduced in 1973. See items 6124.5P and 6133.4P for more photographs of orthorectification equipment.
Physical description
These four photographs of orthorectification equipment were taken at the Army Survey Regiment at Fortuna, Bendigo, c1975 and c1988.
The photos are on 35mm colour slides and scanned at 96 dpi. They are part of the Army Survey Regiment’s Collection.
.1) - Photo, colour, c1975, Wild GZ1 orthophoto projector.
.2) - Photo, colour, c1988, WILD OR-1 unrectified colour photo in carrier, orthorectified and re-scaled colour image.
.3) & .4) - Photo, colour, c1988, WILD OR-1 Orthorectification Workstation
Inscriptions & markings
.1P to .4P – Some of the equipment is annotated on the frame of the 35mm slides.
