35. Marckwardt, W. 
Germany (G.D.R.) 
TESTS FOR COORDINATOGRAPHS 
Testing a coordinatograph is often difficult for users, because test masters in the required dimensions are not 
available. An exception are only those instruments supplying a digitized drawing by means of ‘Datagrid’. In 
all the other cases, either only part of the drawing table can be investigated: by integral tests, or a technique 
must be used that is based on a non-calibrated test master. These integral tests serve for determining the 
accuracy of the drawing table coordinate system which is expressed in terms of mean point errors (static) and 
scale and orthogonality errors. 
A survey of all errors of the coordinatographs shows that in automatically controlled instruments dynamic 
errors play an important part. They are dependent upon the drawing speed and are influenced by backlash, 
inertia and elasticity. Test patterns in the form of pseudo-sine curves, as well as test patterns consisting of 
touching line elements, are suitable for the determination of such errors. 
Special test patterns allowing of being evaluated in a simple way by means of a measuring magnifier are 
recommended to users. These test patterns consist of different elements (curves, straight lines parallel to the 
guideways and with different slopes). They may be used to determine orthogonal errors, affinity errors, statical 
and dynamic reversal errors, and the amplitudes of vibrations. Besides, they should be connected with a general 
functional test. A suitable drawing programme in a storage medium should belong to the equipment of all 
automatic coordinatographs. 
36. Mark, R.P. 
Germany (G.D.R.) 
TESTS FOR MONOCOMPARATORS AND STEREOCOMPARATORS 
With the aim of improving the standard tests for stereocomparators, recommended by the ISP in 1968, 
measurements are suggested with slightly turned grid plates, so that the short periodic instrument errors are 
added to the errors already covered. In this version, the test procedure is better adapted to the practical use of 
the instruments. It is universally applicable, and therefore well suited, for comparative investigations. The 
formulas were derived for a 25 point grid, special emphasis being placed on simplifications in the calculations. 
Measurements with aligned and with turned grid plates can be evaluated by means of statistical tests (F-test 
with regard to the significance of short periodic errors). 
37. Mark, R.P. 
Germany (G.D.R.) 
NEW INSTRUMENTAL SOLUTIONS FOR DIGITALIZATION 
IN PHOTOGRAMMETRIC AND CARTOGRAPHIC PLOTTINGS 
After a retrospect to the state of development in the field of digitalization, the instruments newly developed 
by VEB Carl Zeiss Jena are introduced. These are the electronic digitalizing instrument Coordimeter F with 
manual and automatic release of recording, the small control computer KSR 4100 for recording, data selection, 
data control, etc., the new Ascorecord 2, an interface for connecting digitalizing instruments to plotting 
instruments and a driving system for scanning the models in stereo-plotting instruments in a meander-type 
pattern. Furthermore, the digitalizing instrument of Messrs. Retab, and the Reiss drawing board Digitron with 
travelling carriage, are explained. 
29