Average error ( misclosure ) achieved in analytical block adjustment using electronic 
computer was approximately 50u on the scale of the negative in planimetric detail and 0- 26*/. 
in height. These errors can in no way be called to be representative of the method as 
( © ) control was not signalised ; 
and (i) the film negatives had been subject to wide temperature changes. 
In order to assess appropriate technical specifications relative to the desired product 
and to design suitable procedure to realise these specifications a photographie test area mea- 
suring 36 km by 20 km is shortly being established. Aerial triangulation and optimum 
‘dispersal of trigonometrical points for economic extension of control will be one of the research 
projects. This area will also be used to develop target ( signal ) designs for different back- 
grounds and varied terrain structures. Research will also be carried out to evolve standard 
procedures for high-precision Engineering Surveys and Cadastral Mapping. 
The results of research in these fields are likely to be available before the next Congress. 
Photogrammetric Mapping.—The following photogrammetric instruments are in use in 
the country :— 
Wild Autograph A 7 
Zeiss Stereoplanigraph C 8 
Wild Autograph A 8 
Wild Aviograph B 8 
Kern PG 2 
AMS-2 
Stereomicrometer-Santoni 
Zeiss Stereotopes 
SEG V 
Wild PUG-3 point marking device 
In view of the rapid growth of mapping needs in the country with economic develop- 
ment, a large number of instruments are being acquired. A Gigas-Zeiss Ortho-Projector GZ 1 
with line contour system is also being procured. 
The scales for survey and mapping range from 1/500 for engineering and constructional 
studies to the normal 1/50,000 scale for the basic national map cover. Maps with contour 
interval of 1 metre and larger have been prepared for various users. Orientation of the photo- 
graphic model is carried out using numerical orientation procedure and using electronic desk 
calculators. The following table indicates some of the major representative jobs undertaken 
by the department for production of maps by photogrammetric methods. 
4