1. INTRODUCTION
Analytical photogrammetry has been recognized as a successful
method of extending ground control for map-making since the advent of
electronic computers. However, the degree of sophistication of analytical
treatments of photogrammetry is a direct function of the capacity of the
available computers. Continuous improvements in the design, flexibility
and capacity of modern computers, therefore, encourage corresponding
advancement of analytical approaches to photogrammetry.
For the past few years, various governmental and private organi
zations have developed and tested different methods of analytical aero-
triangulation. A study of these methods reveals a striking similarity, in
basic thinking, between the analytical treatments and analogue techniques.
These similarities may be attributed to reasons such as:
(a) The limited capacity of the computers available at the time of
developing the analytical methods, and
(b) The strong attachment of the photogrammetrists to the well-established
and successfully-tested analogue techniques of which they are
thoroughly familiar.
Now that the modern computers have undergone enormous improve
ments and analytical procedures have been widely accepted, it is time to
consider analytical photogrammetry as independent of, and free from, ties
and analogies with analogue procedures. In this paper, some new concepts
and ideas that are more suitable for analytical photogrammetry are
introduced.
2. A NEW PHOTOGRAMMETRIC OUTLOOK
It can be stated that the basic element of conventional photo
grammetry has been the stereo-pair, defined as the three-dimensional
model constructed by an overlapping pair of photographs. By virtue of
this definition, it has been the general practice to allow for 60% forward
overlap and about 20% to 30% side-lap. These form the fundamental
concepts on which photogrammetric instruments, such as the stereoplotters,
are designed, and the instrumental techniques of triangulation are
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