438
In the figure, a data base (consisting of various stages of
parameter estimation) contains all the. information that. is
required for using digital methods in the various operations.
For instance, existing geodetic control.for.an.area along with
à fictitious data generator and adjustment programs can be used
in "planning" to compute optimum airstation positions and
additional field control requirements, along with predictions
of the statistical estimates of. the aerotriangulation results.
These data can, in turn, be used in the adircraft for navigation
and exposure control, whereby the actual measured coordinates
of the airstation during the acquisition can be returned to the
data base for use as approximations in the adjustments of the
aerotriangulation data. Using standard analytical methods, the
triangulation process computes precise dirstation data for the
photography and thereafter, this data is used directly in the
compilation instrument for data extraction, negating the
repeated orientation process and the necessity for any type of
pre-plotted worksheet. The data base, therefore, becomes the
controlling factor for the entire process and; ‘as such, must be
well designed and general. More inportantiy, the definitions
of the data in storage must be consistenc, unambiguous, and
require a minimum of post- or pre-processing. Likewise, the
algorithms used in the various stages of data manipulation must
be concise, rigorous, and consistent.
A good example of the need for consistency was revealed in a
recent inquiry memorandum mailed to members of Commission II,
WG 11/1, by S. Wu. In the memo, Dr. Wu requested information
on "parameters necessary for the evaluation of an analytical
plotter." His request was prompted by a discussion in Ottawa
whereby the Subworking Group on Software Development decided
that they should focus their attention on "trving to define
those parameters to be used to evaluate an analytical plotter.”
Parameters, in this case was meant to be the numerical descrip-
tors associated with a pair of' pnotographs. The accompanying
questionnaire requested opinions on three basic sets of para-
meters--those associated with the camera, the photography, and
the model. (Of special interest was the list of items associa-
ted with "model paremeters and ground control." On reading it,
one comes to the conclusion that there exists as many "methods"
Of forming a stereomodel as there are analytical systems on the
market. Obviously, with the present variations in hardware and
operating systems, one cannot expect to establish a universal
Software. However, it is reasonable to suggest that a standard
be established for the definition-of parameters and, in some
cases,.the algorithms for computations. If this were done,
data could be easily exchanged and tests of equipment could
thereby pe standardized. °“Early'in the ‘study at the National
Ocean Service, NOAA, it was recognized that any organization
must "standardize in order “fo realize the full ‘potential of an
analytical system.
3
Fh
us look at à graphic description 'o
st an analyti-
tter in figure 3.
Tosamplify, 1
cal stereopio