65 
Adding (262) to (259) we finally find 
1 
Qn = (4n -- 63 n? — 10 » + 12) (263) 
The standard error of the x-coordinates is then 
ma = $9 Ve... (264) 
s, is the standard error of the y-parallax measurements. 
The expression (263) refers to the x-coordinates along the center line 
of the strip. Points along the edges of the strip can be represented 
by the expressions (236) or (238). Evidently the weight number of the 
last term of these expressions can be determined separately and added 
to the expression (263). From (236), (211) and (175) we find the weight 
number 
2 nd? 
3p 
20 
For b — d we have Y which ean be added to the expression (263). 
Evidently the influence of this term can be neglected. The influence 
upon the z-coordinates of the edges of the model from the errors of the 
first model can according to HALLERT 1957 be expressed by the weight 
13 4? : 
number 6 For y — d — b we find ^. Also this weight number can 
) OF 
be neglected in comparison with (263). 
The expression (264) is graphically demonstrated in diagram 15 for 
So l. 
3.212. The y-coordinates 
After substitution of the expressions (213)—(214) into (240) we have 
for the center line of the strip 
i=n i=n i=n 
Dy, — b X (n—3i)dx, 4- X dby, — h & dw; (265) 
i=1 i=1 i=l 
Then we find the weight number as follows 
i=n i=n 
Qu, p Q 4X x (n C 1)? T np, + nh? Quo + 2 5Q,, 2 (n Tem 2) = 
i=1 i=1 
— 2 nhQ, (266) 
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