452 
Summary. 
The report presents a numerical solution of the x-obliquity and the 
width-error according to the grid method in connection with a simul 
taneous test of the accuracy. A group of nine points is used for solv 
ing the problem. This arrangement gives 10 redundant observations. 
The standard error of the x- and y-deviation can be computed by 
means of the standard error of unit weight when the weight coeffi 
cients are known. The problem of adjusting or accepting is solved by 
means of statistics. The level of 5 % is used and the adjustment must 
be made, when the x- and y-deviations exceed 2.23 times their standard 
errors. The fitness of the confidence limits and the incorrectness of 
the usual instructions regarding the checking of the width-error of 
the A8 have been noted in practical tests. Further it has been found 
in series of tests that the instrument needs seldom be checked, only 
twice a year. An example of the performed investigations in accor 
dance with this method is reported above. The root mean square value 
of all the standard errors of unit weight in seven autographs A8 has 
been found to be 5.1 microns. The obtained experiences of the method 
have been very positive. 
References: 
[1] Hallert, B.: A New Method for the Determination of the Distortion and 
the Inner Orientation of Cameras and Projectors. Photogrammetria 
XI, 1954, 3. 
[2] Lycken, L. E.: Numerical Adjustment of X-Inclinution and Latitude in 
Stereoscopic Plotters, Svensk Lantmateritidskrift, 2—3, 1956. 
[3] Kaasila, P.: Zur Justierung von X-Schiefe und Breitenfehler in den Auto- 
graphen A7 und A8. Photogrammetria, 1961—1962:3. 
[4] Firm Wild: Instructions for use Valuable for all A8 beginning with number 
520. 
A cknoivledgements: 
The following persons liave given valuable assistance in the measurements 
and the computations: 
J. -E. Haggroth, Civileng. 
O. Jonason, Eng. 
E. Lidh, Eng. 
A. Muren, Civileng. 
O. Stenkel, Civileng. 
K. A. Ohlin, Civileng.