X'65) 
ly'es) | 
  
magni- 
image 
1). In 
w grid 
round. 
rround 
eter of 
-aphical 
mmetry 
1.2 meter. The coordinates and elevations of the points were determined 
in the geodetic coordinate system with standard errors of about 20 mm. 
Consequently the points on the ground can be regarded as errorless in 
comparison with the errors of the image coordinates, An aerial photo- 
graph of the test area is demonstrated in Fig. 12. In 1958 a series of 
aerial photographs were taken over the test area for among other pur- 
poses, tests of various methods for aerial triangulation. Some of the 
photographs were especially investigated for the purpose of the deter- 
mination of systematic errors. 
The measurements of the image coordinates were performed in the 
right projector of the autograph A7 no. 310. First the single image was 
approximately oriented with the aid of three well distributed control 
points. Then the projected coordinates of the signalled points were 
measured in the coordinate system of the autograph in a fixed enlarge- 
ment. The ground coordinates were transformed into one plane. The 
computations were then performed according to the grid method. In 
order to determine the affine film shrinkage two different enlargement 
factors were used as parameters in the adjustment procedure, see above 
under section 4.221. 
The expressions for the radial distortion can then immediately be 
written as demonstrated in the Table 16, p. 50. 
From the simple computations of the image coordinate measurements 
in two photographs 1 and 2 the following results were obtained, see 
Table 17. 
Table 17. Determination of the radial distortion. 
  
  
  
  
  
| ; Radius | “Image no. 1 Image no. 2 7 | 
| 7 (I. lusum IT. et T 
| aim dr’, | dr y dir | dr’, | dr y | dr o 
[ BE] LE microns 
| | | 
| 126.6 | +97 | —57 | —15 +40 —48 rd | 
| 100.6 +44 | —21 +12 +48 —20 +14 
895 | +54 | —15 +20 +60 —15 +23 
65.0 | +59 | +8 +34 +68 +4 +36 
448 1 +59 | d 8.4 +31 +54 : + 9 ; +81 | 
dr”, and dr' are the radial distortion amounts in the x and y-direc- 
tions respectively. dr’ is the average. 
In the distortion amounts the influence of the earth’s curvature and 
the refraction is included. In Diagram 27 the corresponding radial 
distortion curves are demonstrated. 
The standard errors of unit weight of the image coordinate measure- 
ments were also computed according to well known formulae, The re- 
sults of the computations are demonstrated in Table 18.