46 
Bridging 
After bridging between two control point groups the standard errors to be expected in the model p 
of a strip of n models can with some approximation be expressed as follows: 
= -- -1 ) upo-p)+ 25 1 
h I I p{n—p) 
y ° c f 6n 
10p(n—p) + 107} 
The distribution of the standard errors of the model p = — is shown in fig. 4.5:1 in the Appendix. 
¿i 
4.52 Analytical Model Triangulation 
Cantilever extension 
s x — s 0 — | — (20/i 3 + 54/i 2 -f- 6ln + 3) 
s y = s 0 — ^Yq (^ n3 + 6/i 2 + 50n -j- 18) 
Bridging 
s - = s ” 7 1 2 °P( n ~PÎ + 61 j 
% = s ° 7 ^ + 25 | 
h 
The expressions are graphically shown in fig. 4.5:2 in the Appendix for s 0 —= 1 and for different values of n. 
For the value of s 0 in analytical model triangulation under ordinary conditions a standard error of unit 
weight of 5 um from table 3.3:1 can be used. 
4.53 Ordinary Analytical Aerial Triangulation 
Cantilever extension 
s x — s 0 — I (4ri A -j- 63n 2 —lOn + 12) 
s y = s 0 — 1/ ^ (4/i 3 + 39n 2 - 31/1 + 39) 
s z = s 0 — 1/ n 3 + 6n 2 — lOn + 33 
Bridging 
Sx. Sn 
Ä \/p(n-p) \ 
3/i j 
2p(n-p) + 
■I 
3c 
5 h 
3~c 
. í- \ I P in- P ) + 2 j 
toi j w .- ri + „ j 
h 
The expressions are graphically shown in fig. 4.5:3 in the Appendix for s„ — = 1 and for different values 
of n. For analytical aerial triangulation the ordinary value of s 0 as 5 «m from table 3.3:1 may be used.