7.33 During the year the demand for airphoto and minor control fell somewhat and a concerted effort was made to re-establish the triangulation system, on which all other control depends, on a sound footing.
A total of 58 triangulation monuments was built and a large number of angular observations made. Finally, the whole main triangulation was recomputed and adjusted using the Colonial Secretariat Data Processing Division Computer. Triangulation is being similarly dealt with in sections.
7.34 The minor control survey was also progressed. Considerable progress was made towards computer processing of survey computations and virtually all types of computation used in the survey office can be processed through the computer terminal in Murray Building. However, access to the main computer remains a problem and delays ranging from a few hours to several days are common.
Aerial Surveys
7.35 No aerial photography was possible in the first eight months of the year due to financial restrictions and, towards the end of this period, poor weather. However, from December onwards there were several months of good flying weather and over 2,600 photographs were taken.
7.36 During the year a notable feature was the greatly increased demand for photography from a number of Government Departments such as Housing, New Territories Administration and Agriculture & Fisheries. Many people are now realising that up-to-date photography, enlarged when necessary, provides a wealth of information and, in many cases, is more useful than normal maps or plans, with the limitation that distances cannot be accurately scaled on unrectified photographs.
7.37 One contractor, B.K.S. Surveys of Northern Ireland, continued to carry out photogrammetric plotting and their contract was extended, by agreement, to mid-January 1976. The plotting has all been of a high standard and produced at a very satisfactory rate.
7.38 All the mapping at 1:500 scale requested for the three New Towns was completed as well as a number of tasks for other engineering works.
Photogrammetric Unit
7.39 Early in the year tenders were placed for the supply of the main photogrammetric equipment.
7.40 The Unit was allocated very good accommodation on the 2nd floor of the San Po Kong Government Office. Extensive alterations and fitting-out were required, including floor reinforcement for the larger machines which weigh nearly two tons each, 24-hour air-conditioning for temperature control and a photographic darkroom.
7.41 The four stereoplotting machines were all installed and calibrated by the end of January and this coincided with the return of the four technicians and one Land Surveyor from their overseas training. After the successful conclusion of their 9-month formal training in Holland the technicians had spent 3 months on production work with B.K.S. Surveys in Northern Ireland.
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