ENG-1981 — Page 175

HOUSING AND LAND

Survey

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The Survey Branch of the Crown Lands and Survey Office provides a network of trigonometrical stations and benchmarks upon which all land and engineering surveys are based, and for mapping of Hong Kong and the delineation and physical marking of boundaries of lots.

The branch's photogrammetric unit supplies detailed survey plots for engineering, geotechnical control and development purposes; during the year it was also able to make good progress on contouring for the standard metric 1:1 000 series of plans. Aerial photography for photogrammetric plotting purposes, and for engineering and environ- mental studies, is supplied by the Air Survey Unit, assisted by the Royal Hong Kong Auxiliary Air Force.

Following the completion of the new main survey control system, in 1979, converting and adjusting minor control to the new system continued and the exercise was virtually completed in 1981.

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Cartographic projects undertaken by the branch during 1981 included continuation of the revision and reprinting of the 1:20,000, 1:50 000 and 1:100 000 map series; Hong Kong. Streets and Places Volumes I and II; the Hong Kong Official Guide Map (fifth edition) and the Countryside series of sheets one to four. Sheet five of the Countryside series maps, New Territories northeast, was published during the year. The production of the 1:5 000 series for the New Territories continued with 20 of the 160 sheets having been completed. The cyclic revision of 1:2 500 and 1:5 000 urban and the street plan series was maintained according to the programme.

The metrication of the 1:1 000 basic mapping series continued slowly. Extra staff approved for this task will improve the production rate once they are recruited and trained. Specific-purpose maps illustrating country park facilities, district administration bound- aries and Tolo Channel and Junk Bay water control zones were also produced.

Sales of maps, plans and aerial photographs to the public in the year surpassed $1 million for the first time. The sum is made up about equally from the sale of coloured maps to the general public and from the sale of large scale plans and aerial photographs to engineers and developers.

The Public Works Department's Survey Training School provides training for the certificate course in land surveying (a course organised with Hong Kong Polytechnic), basic cartographic course and other elementary surveying courses. During the year, 258 government officers attended various courses at the school.