TABLE 5 gives the scales of negatives, models and maps and in addition the dimensions 
used for the signals for each of these scales. Those signals are used to mark control points, 
points for later terrestrial surveys, boundary points, auxiliary points for field completion 
surveys. The standard error of control points determined by ground survey is 5 cm in 
planimetry. Since the cadastral service is only concerned with planimetry no values for 
the accuracy in height can be given. The Cadastral Service reported to Commission IV a 
standard error m, of signalized boundary points, mapped from photographs in the scale 
1 : 6.000 of 5 cm which is equivalent with 8 micron in the negative. The standard error 
of distance m, is given as follows: 
0 to: 10m 5 cm 
10 to 30 m 6 cm 
30 to 100 m 7 cm 
100 and larger 8 cm 
As far as the errors are not correlated, the value of m, should be equal to m,. Since, 
however, a great many sources of errors have about the same influence on the machine 
coordinates of points located in the diapositive on very short distances, the coordinates of 
these points from which we compute the distances are strongly correlated. Consequently 
we will find m, smaller than m,. Dr. Härry found m, for various distances between 0,30 
and 0,80 times m, and as an average 0,50 m, (Photogrammetria 1957—58 page 146). The 
result of the Netherlands Cadaster seems to be contrary to this theory and the standard 
deviation in the absolute position should have been 2 times 6 — 12 cm. Further discussion 
with the Cadastral Service learned me that the m, — 5 cm was not computed from the 
differences between photogrammetric and terrestrial coordinates of arbitrary pre-marked 
points because of mistrust of the precision of the ground survey. The value of 8p, corre- 
sponding with 5 cm was found from the differences between the machine coordinates of 
about 150 points (in 2 models) determined with 5 repetitions of each absolute orientation 
and 4 readings of each point in each absolute orientation, divided into 2 cycles. It is 
evident that these 20 machine coordinates are correlated and consequently cannot express 
the absolute precision. The 8 u represents the precision of the restitution procedure as such. 
IV/3.b and c. Survey Department of the Ministry of Transport and Waterstaat; K.L.M. 
Aerocarto N.V. 
For the smaller scales, for instance for the river maps in the scale 1 : 10.000, this service 
uses a scale of the negatives between 1 : 10.000 and 1 : 20.000 taken with the Wild R.C 5 
filmcamera. For the larger scale mapping both the Wild RC 7 plate camera and the Zeiss 
convergent Twin camera are used. The general rule is that the Zeiss convergent Twin 
camera is used when adequate ground control is available for plotting each model, whereas 
the Wild RC 7 vertical photography with plates is used where an aerial triangulation has 
to be carried out to obtain secondary control. In some cases, however, bridging of a pair 
of convergent photos has also been carried out, the results of which however, have so far 
been below expectations. 
For the smaller scales, as for the river maps 1 : 10.000, photo-scales larger than 1 : 20.000 
appear to be more favourable due to reduction of field completion surveys. This went so 
far, that during this period the photo-scale was brought to 1 : 10.000 whereas the plotting 
is done in the Wild Autograph A 6 in a scale 1 : 5.000. Map reproduction is carried out 
by photographic means after the field completion has been plotted. 
For the larger scale plotting of maps 1 : 2.000 and 1 : 2.500 a negative scale 1 : 6.000 
to 1 : 10.000 was chosen. For maps 1 : 1.000 and 1 : 500 the negative scale was between 
1 : 6.000 and 1 : 3.000. In some cases the negative scale 1 : 2.000 taken with the Zeiss 
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