-h- 
most obvious application, I feel that these thoughts on the subject are important 
enough to be given thorough consideration. 
Super-wide-angle photographs 
The impact of super-wide-angle photography on photogrammetric opera- 
tions was initially not as great as one expected or hoped for. The reason may 
be twofold: initial instrumental difficulties in plotting and secondly, some- 
what inferior definition of super-wide-angle photographs. The super-wide-angle 
lenses were developed before plotters that could accept super-wide-angle 
diapositives of original size were available, This, of course, delayed the 
acceptance of super-wide-angle photographs in many standard topographical mapping 
operations. But, analytical aerial triangulation and availability of moderately 
priced detail plotters that can accept original size wide-angle photographs, 
removed this difficultly. However, the stimulating effect of the initial 
development was somewhat lost. It is also probable that in the meantime many 
agencies have acquired plotters not necessarily tailored for use of super-wide- 
angle photographs. 
This development, if my analysis of the situtation is correct, is 
rather unfortunate in view of the definitely superior accuracy in elevation 
obtainable from super-wide-angle photographs as a result of larger base to flying 
height ratio [8] and other important technical and economic advantages. One of 
these advantages is the ability to reduce the level of the flight which makes it 
significantly less expensive. Particularly in mapping projects of less developed 
areas, use of super-wide-angle photographs should result in overall improved 
efficiency and reduction of costs. 
Colour photographs 
  
With the rapidly growing use of aerial photographs in various disci- 
plines, mainly for photo-interpretation purposes, the interest in colour photo- 
graphs is steadily increasing. This trend is understandable. A further increase 
of interest in this direction should be expected, particularly since it is likely 
that colour orthophoto maps will provide an additional incentive. 
Photogrammetric Engineering and The Photogrammetric Record relatively 
recently published some interesting articles on the subject. Instead of 
repeating various arguments for the use of colour aerial photographs, I would 
like to record the fact that the main difficulty in using colour photographs 
lies in the interphase operation: production of colour glass diapositives is 
not mastered yet and the diapositives consisting of the colour film transparency 
glued to a glass plate occasionally produced are prohibitively expensive. It is 
also true that the results from colour photographs are somewhat worse, as far as 
accuracy is concerned, than the ones from usual black-white photographs. There 
is little information on this subject and, therefore, I am including our own 
results obtained from experimental flights over a very precise test area. 
  
  
NRC - Monocomparator 
  
Diapositives Standard error | Number Total 
in photoscale of Number of 
mx my mz | Models Points 
  
  
Panchromatic black-white, Su óu | 10u 22 906 
estar base glass 
Kodak Fktachrome black-white, Tu Tu | 15g 10 333 
M5, estar base glass 
colour, on on | 134 | 117 
glass 
  
  
  
Difference in accuracy between a and c c 30%