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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