which are approximately 2/3 of those listed in Table III. In this case standard 
errors as show in Table IV are to be expected. 
TABLE IV STANDARD ERRORS AT TEST POINTS AFTER BLOCK ADJUSTMENT 
Number 
Standard Errors 
of Tesr Polnst 
M x 
My 
M p 
M 
E 
165 
± 4.3 m 
± 4.6 m 
i 63 m 
=b 6.0 m 
A glance at Table II shows that strips 1 and 4 in particular produced large discre 
pancies and have a considerable lower accuracy when compared with the other strips. 
It seems to be probable that some fairly large identification errors at the ground control 
points are the reasons for these discrepancies. The low accuracy of these two strips, 
of course, affects the accuracy of the entire block triangulation resulting in relatively 
large standard errors. 
5 — REQUIRED TIME FOR THE VARIOUS PHASES OF THE BLOCK TRIANGULATION 
(( MASSIF CENTRAL » 
A Examination and Calibration of the Wild Autograph A7 . 25 man hours 
B Preparation for instrumental work (planning, drawing of 
overlap, triple overlap, and sidelap on paper prints, selection 
of transfer points and common points in the sidelap areas, 
computation of bz-values for the aerolevelling method) . . 182 man hours 
C Performance of the strip triangulation at the Wild Auto 
graph A7 308 man hours 
D Final computational model connection (final connection of 
adjacent models in each strip) 88 man hours 
E Coordinate transformations 66 man hours 
F Strip adjustments 92 man hours 
G Block adjustment 52 man hours 
Total 813 man hours 
This total of 813 man hours represents approximately 2 hours and 55 minuts 
per model. 
6 FINAL REMARKS 
The performance of. the block triangulation « Massif Central » has shown that 
the identification errors at ground control points and test points have critically affected 
the results of the block triangulation. This means that the computed standard errors 
probably do not reflect the real inherent accuracy of the method applied. For future 
tests it is recommended that more detailed and clearer sketches of the ground control 
points and test points are provided or that signalized points are used. The standard 
elevation error obtained in using the aerolevelling method is much larger than can 
be expected for this method under comparable conditions. This leads to the conclusion 
that either the statoscope did not function properly, or that there were excessive ano-