-7- 
Since the height differences will rarely reach the ex 
treme values of 5 - 6 - 10 - 30 meters on a single photograph, and 
the resulting radial displacements' are still minimized in the recti 
fication, it may he said that the accuracy obtained will he well 
acceptable within the limitations of the Aviogon photography. 
In order to appreciate the final accuracy of the con 
trolled mosaic one has, obviously, to consider the various sources of 
error: identification and point transfer, ground coordinates, pre 
paration of templets and grid, instability of all the types of paper, 
material and bases used, rectification and lab, mounting, etc. As 
the influence of these sources can hardly be weighed in practice, on 
ly a few references will.be made under the following headings. 
The photographic coverage consists of 29 strips and was 
carried out in 6 flights, during the month of June - 1962 (See figure 
2)« The total number of exposures was 1.347* One of the'strips (51 
exposures) had to be repeated. 
3, - GROUND CONTROL 
As ground control for the triangulation, the coordina 
tes of 273 points, were supplied. All these points had been computed, 
through aerial bridging, and had been used for the plotting of the 
l/50 # 000 map series. 
The accuracy of the-se coordinates,- in terms of the mean 
square error, is mp = ± 10 meters. This can not be considered favou 
rable for a controlled mosaic at 1/10,000, 
The location of these points was given graphically in 
a collection of the 1/50,000 contact prints. On account of the large 
density of control, only the well identified points were transferred 
to the l/20,000 photography. These points, 210 in number, were main 
ly distributed in the vicinity of the edges of the outer strips. In 
the course of the slotted templet assembly, approximately 9$ of those 
transferred points were further discarded. 
4, - CONTROL FOR RECTIFICATION AND MOUNTING 
The desired scale of the mosaic* was, as said before, 
1/10,000, Since■the scale of the photography is 1/20.000, the pos 
sibility of rectifying at this scale, mounting and then enlarging the 
mosaics twice to 1/10,000, was considered. 
The reproduction camera available - a Barcro, manufactu 
red by E,N. Mason & Sons Ltd. and acquired in 1949 - would not allow 
such a solution since accuracy, image quality and loss of detail would