THE CROSS BASES METHOD FOR UNEXPLORED REGIONS 
  
  
   
  
  
  
i 
| 
| 
| | c 
| | | 
| | 
Xe X2 | X, X 
œ CON " 2 
$ e q a 
3 e y v 
À dj d " 
A Q 
dN A 
  
  
  
  
  
  
  
FIG. 
The adjusted coordinates and elevation of 
any point P wil then be: (X,—AX,) 
(Y? —AY,) and (H,—AH,). M the elevations 
measured in the field do not permit the direct 
determination of dóo and dy from correspond- 
ing diagrams, these last mentioned values 
could be easily computed from the formula 
for AH, using three measured elevations dis- 
tributed along the length of the strip. 
In case of aero-leveling, the adjustment 
formulae are as follows: 
oS dx? | dAx-dxo dAx?) 
AX, =X d$. 
| | 2 773 2 12 
8S dxo-dAx , dAst 
Ç TT Ç 
à — 75 4b | 
rg) dAx* } X y) T dAx | 
l 6b? \ l b 
Y! : dxo| 
lAx 
MY.m Yidul d XH a yiaso 05; 
( 2b 
ye) E dAx S di + XY (85) 
l b 27 (b | 
I 
* í r n SO À Zz : 
AH, = | -— Z(dSo — éS)í + X ) —— 55 
b 
j ,(dAo 
+ XF4- | 
( b 
. (ZdAx 
+1 i - 
- dey — dvo 
b 
These adjusted coordinates could then be 
transformed in any local system of coordi- 
nates adapted. 
Although the aerotriangulation and the ad- 
justment could be accomplished with the 
minimum requirements as shown, it is ad- 
visable and strongly recommended that more 
than these minimum requirements be meas- 
ured in order to take into account eventual 
irregularities in the propagation of errors, and 
the frequent deviations from the ideal condi- 
tions of the flight and terrain assumed in de- 
riving the formulae. 
ATTAINED ACCURACY AND CONCLUSION 
Experiments carried out by the author on 
the Wild A7 of the Swiss Federal Institute of 
* Statoscope errors not included, should be 
treated separately. 
  
— EROR AERIS. E 
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