„18 - 
range photogrammetry require facilities that allow for considerable 
freedom in mathematical modelling, data processing and presentation of 
results, The causes for these requirements are: the need to use 
different types of metric and non-metric cameras as well as data 
acquisition systems that can be regarded as cameras only in the most 
general sense, the need for unorthodox positioning and orientation of 
these cameras, and the need for specialized output forms [18]. These 
complexities dictate the use of adequate means for determination of 
orientation parameters, and adequate techniques for correction of 
systematic errors and for assessment of the accuracy and reliability 
of the results. As can be seen even from a superficial review of 
applications in close-range photogrammetry, these factors are respon- 
sible for the overwhelming analytical processing of data. With the 
exception of trivial cases most of the problems are solved by off-line 
analytical methods. These methods, although allowing for a very 
flexible mathematical modelling in respect to the orientation proce- 
dures, do have inherent shortcomings in respect to the compilation and 
presentation of acquired information, The most obvious are: the 
impossibility to reconstruct the stereo model at the time of compila- 
tion, and the limitation of data collection to discrete point mode. 
The use of analytical instruments in close-range photogram- 
metry offers, besides the obvious advantages related to orientation 
procedures, a number of other advantages that are based on some funda- 
mental properties of these instruments. They are: the real-time 
transformation of coordinates between coordinate systems in the image 
space, model space and any other reference space; the freedom of choice 
of these coordinate systems (e.g. curvilinear); the simultaneous 
presence of all the sets of coordinates, for the observed point, in all 
the coordinate systems defined by the basic real-time program; computer 
control of all positioning devices, displays and input-output devices; 
the real-time or near-real-time computation of quantities derived from 
coordinates; use of redundant observations for on-line adjustment and 
statistical analysis of intermediate or final results; the continuous 
feedback of information to the operator; and the capacity for automa- 
tion of processes. 
The significance of these properties becomes evident when con- 
sidering that in close-range photogrammetry every application has its 
own peculiarities in respect to collection, processing and presentation 
of information. From the earlier general discussion of orientation 
procedures it is also evident that many orientation problems of close- 
range photogrammetry, when the effective on-line reconstruction of a 
stereomodel is desired, can be successfully solved only by analytical 
instruments (e.g. simultaneous least square determination of eighteen 
parameters for non-metric camera images, orientation of images gene- 
rated in other than central projection). The compilation procedures 
are somewhat more difficult to analyze without a precise definition of 
the goal of a specific application and of the circumstances under which 
that goal should be attained. But one can form, by analogies and 
induction, a general idea about the significance of analytical instru- 
ments for these operations in close-range photogrammetry, on the basis 
of the following examples. 
If a measurement of coordinates on a certain set of points is 
performed by the operator, these coordinates can be stored and used