undertaken with the RC10 camera to assist in the revision of certain areas in the New Territories using a recently developed method of field control combined with comparison of photography enlarged to plan scale. This has helped to speed-up 1/1,200 scale revision, and it is expected that revision of additional areas will be covered as part of the proposed new photogrammetric contract.
7.21 The accurate control system established for fixing points on the alignment of the Mass Transit scheme was broken down further and is now being incorporated into the entire control traverse network in the urban areas. Check surveys on Mass Transit site plans plotted to 1/200 scale, carried out by two firms of private surveyors for the Consulting Engineers, were completed by staff of the Control Section.
7.22 The large-scale survey plan redrawing programme was drastically curtailed during the latter half of the year, pending introduction of the new metric (S.I.) scales on which much effort was expended on sheet and specification design as well as production planning. Title drawing work was rather surprisingly down on production over the year, while the Photo-reprographic and Sales sections had record productive years.
Control Survey
7.23 Following closely on the traverses established to the maximum degree of accuracy along the proposed Mass Transit routes, the use of Electro-magnetic Distance Measuring Equipment has enabled re-measurement of existing control traverses and the fixing of new control traverses to be tied in quickly and accurately to this Mass Transit control.
7.24 An increased amount of control traversing was established in the New Territories to assist in the revision plans of developing areas and as a basis for the fixing of photo-control points in areas being plotted by photogrammetry from aerial photography. Permanent marks were also established in certain areas where the proposed New Town development is considered to have priority requirement.
Mapping
7.25 The number of 1/600 scale sheets fully revised decreased by about 5% this year but the number of 1/1,200 sheets fully revised showed an increase of more than 30%. This substantial increase in
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