74 
We substitute the expression (139) and the following relations into (304) 
  
  
i-n (n — p) (n — p + 1)(2n — 2p + 1) ; 
2 (14+ n—1)2= = (305) 
i=p+1 6 
i=p pn 2p+1)2p —1 
À (2: — LP — pli Jt ; ) (306) 
i-1 3 
i=n (n — p) (2n — 2 p 4- 1) (2 — 2 p — 1) 
X (2a—i£idqgglc—M (307) 
i=p+1 3 
i=p (4 pP — 3 p — 1) 
à (—1(2i— 1) DU EP = T (308) 
i=1 6 
iR : : (n — p) € l r* 
2 (1+n—1)(2n—22+1)= o (n — p)(£n—4p- 3)-— |}; (309) 
i=p+1 
Further the weight numbers (176), (177), (180) and (257) are inserted 
into (304). After some elementary calculations and rearrangements we 
find 
p (n — p) pe 
Qryry = - 60 {2 p (n — p) + 1} [1 + 3 (310) 
For b — d we finally find 
p (n — p) : 
Qn,n, — 2x v (250—545 (311) 
The standard error is as usual found as 
mp, = So | n.n, (312) 
where s, is the standard error of the y-parallax measurements. See 
diagram 16. 
The formulae (311) and (312) demonstrate the error distribution of 
the transformed z-eoordinates along the center line of the strip but 
with certain approximations. First the errors of the measurements in 
the control points and in arbitrary points are not included. Evidently, 
these errors can be taken into account in adding the corresponding