PHOTOGRAMMETRIC ENGINEERING 
  
  
  
  
  
  
  
  
/ OH 
OH, H,0 
Fıc. 1 
ox” H, © 
§ Az 
9, A" 5 
T Oo A, sut 2 Qo 
B, B 
FIG. 2 
The triangulation on the stereoplotting ma- 
chine proceeds in the same manner as the 
classical (coordinates) method, with the ex- 
ception that the absolute orientation of the 
first model is not necessary. For instance, the 
triangulation could be carried on with the 
first photograph horizontal. The strip adjust- 
ment takes into account the effects of neglect- 
ing the absolute orientation of the first model, 
as will be shown later. From the machine co- 
ordinates and elevations of the critical points 
(the end points of the cross-bases and the 
points known in elevation) the following ele- 
ments (quasi-observations) could be deter- 
mined for each cross-base: Its length L,, its 
azimuth À, and its lateral tilt Q,. These val- 
ues, when compared with the terrestrially de- 
termined ones, will give us the following er- 
rors in the quasi-observations for each cross- 
base: 
= Scale Error 
AA = A; — A = Azimuth Error = A0 
AQ = Q — Q = Lateral Tilt Error 
If the determined elevations of the control 
points permit determining the longitudinal 
tilt at both ends of the strip (as in Figure 2), 
the error in ® will also be available. (In such 
a case, ® would be our fourth quasi-observa- 
tion.) If this is not the case (see Figure 1), we 
just determine the errors in absolute heights. 
In this case: 
AH = H, — H = Error in absolute height. 
The theoretical and practical investigations 
carried out by the author* show clearly that 
the greatest part of the effect of the system- 
atic as well as of the accidental errors seems 
to be systematic. This important fact permits 
* See Bibliography (3). 
drawing the diagrams in Figure 3 and to de- 
duce the given relationships. 
Once the elements of the quasi-observations 
are determined, the adjustment of the strip is 
carried out very easily with the aid of the 
simple formulae that are deduced by superpo- 
sition of the effect of the different quasi-ob- 
servations on the coordinates and elevation of 
any point P (Y, Yp Kp). 
In case of aerial polygon, the adjustment 
formulae are as follows: 
; ( oS dx? dxo . dAx dAx? 
X - dSo — "mm of + _ - 
| 2 2 2 12 
do? d$»: d^ 
2 7 12 | 
dxo: d Ax L dAx? dóo: d^ : i 
2b 4b 2b 26) 
d^ 2 1 / 
6b? 6R? ) 
AX, = 
ly? 0S 
edil | x} 
— —— 
(2b 
724 dAx? 
i 6b? 
( dAx ) 
hy FE Yi 
| b 
1Ax 
2) : y + Y1idS, — 5S! 
LU 
; y? \ dAx dAw / 
E 27 | 
— dxo! 
AY, = X{dwo} + X 
= 105) 
( b i) 
“ZdSy — 55)} + X 8S — dd» 
viz Eden — dan} 
| 
{ Inall the diagrams and formulae, b is the mean 
base length, Z is the mean flight-height above 
ground. The elements of orientation are given in 
the symbols normally used. R is the earth radius.