-3-
be bridged. In odd cases, however, where the accuracy of aerotriangu-
lated elevations is, for some special reason, the critical value, the
mbd charts and equations have to be used in a slightly different way.
Details on this point will be given later in an example.
Figures 2 and 3 show two universal mbd charts developed at the
University of Illinois for the cases of 60% and 70% longitudinal over
lap, respectively. Figures 2-a and 3 -a are intended to supplement
Figures 2 and 3 for the small range of/lj_| and mbd. Charts 2, 2-a, 3 and
3-a are worked out with the following restrictions in the different
parameters:
1. Accuracy requirement (mean square error) in planimetry: +0.02 in.
(±0.5 ram) measured on the publication scale of the map.
2. Accuracy (mean square error) of measurement of parallax in a
stereoscopic instrument: +0.0004 in. (+0.01 mm) (in image plane).
*+
3« Relative Orientation: According to Bachmann
4. Aerotriangulation: Instrumental conjunction of successive photo-
graphs without auxiliary data , generally termed "Aeropolygon".
5- Ground Control and Adjustment: Cross Bases Method
6. The chart could be used for aerial cameras with principal distance
ranging from 3 in* ** *** to 12 in.
* A summary of this method is given in the Appendix. For complete
details, see Bibliography Entry No. 1.
** Better known by its German name "Folgebildanschluss”. For details
see Bibliography Entry No. 2.
*** See Bibliography Entry No. 5 or 9.
+ For all practical purposes, however, any other method could be
used. Experience has shown that there is no substantial difference
in accuracy between the different methods.