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11 
FAIREY SURVEYS LTD 
Aerial photography and photogrammetric plotting was undertaken of the 
wreakage of two pylons on each side of a wide river over which high tension 
electric cables were carried before they were blown down in a freak storm. The 
plots of the crumpled steelworks were used in the course of investigations to 
determine the reason for their collapse. 1:2500 vertical photography, exposed 
in a Wild RC5A camera, was used to make plots in a Wild A8 Autograph. 
Another project was concerned with car parking statistics. Conventional 
vertical aerial photography was taken at half-hourly intervals over the period 
of a day in a west country holiday resort at the height of the summer. The 
photography gave full stereoscopic cover of the town at each pass. The data 
was used to obtain statistics concerning car parking in the town: e.g the 
duration of kerbside parking, the rate of turnover in central, off street, car 
parks, and so on. The work was mainly carried out by the staff of the local 
authority who commissioned the flying. 
Another project involved the survey of a rock face. Horizontal 
photography of the North face of Edinburgh Castle Rock (40) was taken with a 
Wild RC5A aerial survey camera in a special mounting from an elevated 
hydraulic platform (normally used for maintaining street lights). The photography 
was subsequently used to plot contours, with reference to a vertical plane, at 
horizontal intervals of 250 mm at a scale of 1:50, in a Zeiss Stereoplanigraph C8. 
The survey was used in connection with surface stabilising and rock bolting being 
carried out by engineering geologists. 
In another project, photography taken with a horizontally pointing camera 
installed in a Dakota aircraft was used to measure the visible heights of storm 
clouds. The aircraft was also equipped with radar as well as instruments to 
measure and record accelerations in pitch and roll. The radar antenna was 
pointed towards the storm clouds at successively varying vertical angles whilst 
horizontal photography and photography of the radar screen was taken 
simultaneously. Using the range given by the radar, the inner orientation of the 
camera and the other records, the heights of the storm tops - both visible and as 
seen by the radar - were calculated by triangulation. 
Another project involved the measurement of a steel mould. Three 
dimensional co-ordinates were produced photogrammetrically of a steel mould, 
approximately 0.4 m x 0.4m x 0.1 m. Photography was taken with multiplex 
projector lenses and the resulting negatives were reprojected through the same 
instrument to make the plot. A regular grid of three dimensional co-ordinates 
over the area of the mould was measured. The grid spacing was 1/4 inch. 
In another project stereometric photography was taken with a specially 
mounted Galileo-Santoni camera (special "A", 520 mm. base stereometric 
camera) of an area approximately 1000 mm x 1000 mm centred on the static 
vent area of a jet airliner. Networks of spot readings on regular grid layouts of 
10 mm x 10 mm and 30 mm x 30 mm were measured photogrammetrically in a 
Zeiss (Jena) Stereometrograph "E". The purpose of the measurement was to test 
the feasibility of photogrammetric methods for measuring deformations on the 
skin of the aircraft in the vicinity ofthe static vents in connection with wind flow 
tests affecting calibration of aircraft altimeters. 
The photogrammetric plotting from stereogrammes of children's faces, 
which was reported at the ISP 1968 Congress, has continued on a regular basis. 
(39) and à number of routine aerial survey contracts have been carried out where 
volumetric measurement has been required.