General
7.25
As stated earlier in this report the year witnessed a slackening in land transactions and this enabled staff normally engaged on title surveys to be transferred to urgent surveys associated with air photo control for the New Town projects or diverted into constructive mapping duties.
7.26
Despite assistance from diverted title survey parties, the goal of a realistic map coverage within the Colony still continues to place a heavy strain upon capacity. In the absence of photogrammetric plotting machines, the Survey Branch continues to use the conventional methods of intersected control points to rectify photography enlarged to map scale.
This method, however, is limited to flat areas in the New Territories with the result that the Photogrammetric Unit, if established, will be faced with a heavy workload in covering the hillier and more difficult areas. The Hong Kong and Islands Division has been examining the reorganisation which will be needed within the Branch if current proposals for a P.W.D. photogrammetric unit are approved.
7.27 Metrication continues with the addition of a metric grid to survey sheets, the conversion of records and the formulation of new survey and mapping specifications. Possibly the greatest problem of metrication is the conversion of contours from Imperial to Metric values on all the large scale survey sheets. The only satisfactory way to achieve this is by re-survey using aerial photography and photogrammetry and it is proposed that this will be a major task of the P.W.D. Photogrammetric Unit. Full conversion to the Metric System will take a number of years to complete. It will require a great deal of effort as it must be achieved largely with existing staff resources and with minimum inconvenience to all users of maps and plans produced by the Branch.
CONTROL SURVEY
7.28
Control survey work in the urban areas of Hong Kong and Kowloon has been reduced to a minimum during this year and the utmost effort expended on establishing additional minor trigonometrical points in the New Territories, in preparation for work to be carried out as part of the New Territories Development programme.
7.29
This control is required as a basis for the air photo control being carried out to implement the metric mapping of the areas of the N.T. scheduled for development. A record number of air-photo control points have been established during the year.
7.30
The Mainland Division has set up Sub-Divisional Survey offices at Sha Tin and Tuen Mun, making a total of 6 in the New Territories.
Local Air Survey
7.31
RC 10 photography from the R.H.K.A.A.F. "Islander" continued during the year providing cover of many areas of development, including civil engineering sites, highway alignments, quarry sites and areas of proposed development in the N.T. This vertical photography has also been used as a means of revising existing survey sheets in the N.T. areas using a locally devised method of plotting from enlarged photographs controlled by surveying.
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