increasing amount of work connected with Town Planning. Additionally, increasing demands were made for special work such as plans for tourists and street guides.
Local Air Surveys
6.19. A modified air survey camera was obtained on loan for experimental air photography which was carried out by one of the Division's Land Surveyors. The main purpose of the experiments is to ascertain whether air photographs of sufficient precision can be taken in all conditions, to enable the measurement of earthwork quantities on site formation contracts by subsequent photogrammetric measurements, to be fed into a computer. The experiments are continuing.
Surveys for Government Projects and Other Departments
6.20. (i) Special Air Surveys for Waterworks Projects
During the year priority in air survey mapping has been given to the areas of the Sai Kung peninsula where the Waterworks Office and their consultants are carrying out investigations for water resources. Arrangements were made with Hunting Surveys Ltd., to produce special plans at 1/600 scale, with five feet contours, of the possible dam site areas. A special task carried out in May 1967 was the capacity survey of Plover Cove Reservoir during the short period when most of the sea water had been pumped out and before the summer rains commenced. Ground control points which could be precisely identified on air photographs were accurately surveyed and capacity tables were computed from the air photographs which gave the volume of water contained in the reservoir at each inch of water level.
(ii) Site surveys and setting out
The number of large scale site surveys, mainly for the Architectural Office, continued to rise; a total of 128 sites being surveyed. In addition, an increasing number of requests was received for the setting out of roads and Government buildings.
(iii) Check surveys on Site Formation Contracts
The number of Architectural Office site formation contracts on which the Survey Division is carrying out interim checks at regular intervals has risen to seven. An increasing number of staff is now employed virtually full time on this work, which is required to assess interim payments to contractors.
72