r 
30 
Weight distribution of projector coordinates of plotting 
instruments 1960 
Autograph A7 
So io-inm Base ; zero 
Ste r eo p I a n i g ra p h C8 
B ase : zero 
Average of 6 test s 
Four correction glass plates for A8 autographs and belonging to the \IAK company in Stockholm 
were tested together with glass grid nr 410 in the StK 824 stereocomparator at the Division of Photo- 
grammetry of the R. Institute of Technology in Stockholm. The grid method was used. The results 
of the comparison between the radial distortion curves obtained from the tests and the corresponding 
radial distortion to be compensated are shown in fig. 2.4:1 in the Appendix. The averages of the standard 
errors of unit weight with change of radial distance are also shown and prove to be small (the average 
is about 1.3 /tm). This indicates good symmetry of the plates and high quality of the test measurements. 
The deviations are similar for all four plates and are generally less than 2 «m. 
In fig. 2.4:2 and 3 in the Appendix the results of other projector correction glass plate tests are shown, 
indicating good symmetry, but with some residual systematic differences. For significance tests, informa 
tion concerning the accuracy of the given values of radial distortion must be available. 
In fig. 2.4:4 through 8 in the Appendix results of tests of diapositives from a projection printing 
apparatus (at the Geographical Survey Office in Stockholm) are shown, with and without compen-