2 
COMMISSION III.. AERIAL TRIANGULATION 
Rapporteur: Mr. P.L. Meadows 
Since 1964 considerable interest has been shown in analytical aerial 
triangulation in South Africa. A few photogrammetric establishments 
have already adopted analytical, in preference to analogue procedures, 
for map production purposes at all scales, while others are actively 
experimenting in the application of analytical techniques. 
These experiments include the use of precise stereoplotting equipment as 
mono- or stereocomparators, methods of independent model triangulation 
and the development of suitable computational methods using electronic 
computors. Both analogue and analytical block adjustment techniques 
are used regulaNy for large and small scale mapping. 
Research projects have included the weighting of models and pI animetric 
accuracy in single model triangulation, the use of polynomials in strip 
and block adjustment, use of precise stereopI otters as comparators, and 
relaxation block adjustment methods. 
COMMISSION IV. MAPPING FROM PHOTOGRAPHS 
Rapporteur: Mr. P.W. Thomas 
The basic scale of the South African national mapping programme, con 
trolled by the Trigonometrica I Survey Office, remains at 1/50 000 and 
over 50$ of the Republic is now covered at this scale. Much of the 
work is undertaken departmentaI I y, the remainder being carried out by 
private land surveyors and commercial air survey companies. To in 
crease the speed of production and supply a map more acceptable to the 
user, experiments have been made with Photomaps, Edge Outline maps, and 
Orthophotomaps. . It appears that these may have definite applications 
in the Repub lie. 
In Rhodesia photogrammetric methods are employed by the national map- 
pi ng agency in the production of the 1/5000 and 1/50000 series from 
photography at 1/25000 and 1/60000 respectively. 
The South African Department of Transport makes extensive use of photo- 
grammetric procedures in compiling I/4800 route location and 1/1200 
design plans for proposed National and Special Roads, as well as the 
location and design plans for aerodromes. In numerous other central, 
provincial and local government agencies photogrammetric plotting 
procedures are continuing to find increasing favour. 
Altogether nineteen commercial air survey companies operate in South 
Africa (17) and Rhodesia (2), undertaking aerial photography, mosaic 
production and mapping at various scales, as well as such related op 
erations as geo-physical prospecting, etc. 
Research activities have been confined to the International Experiments 
controlled by Working Group IV/I and IV/5.