20. Masry, S.E. 
Canada 
HIGHWAY APPLICATIONS OF THE ANALYTICAL PLOTTER 
The computer-control feature of the analytical plotter allows the movements in x- and/or y-directions in the 
model to be performed automatically in a pre-selected pattern. That, combined with the possibility of 
manipulating model coordinates during the measurements, makes the instrument most suitable for highway 
applications. 
The plotter was programmed for semi-automatic cross-sectioning and profiling. The result is a considerable 
saving in time and a reduction in the amount of tedious work on the part of the operator. In addition, 
information necessary for the design, and which requires separate processing in the case of conventional 
plotters, can be obtained in the same process. 
Research is being carried out to determine the most suitable horizontal and vertical alignments directly from 
the stereo-model in an interactive fashion. The techniques followed are described. 
21. Mullen, R.R. 
United States 
van Wijk, M.C. 
Canada 
van Zuylen, L. 
Visser, J. 
Netherlands 
PERFORMANCE AND APPLICATIONS OF ORTHOPHOTOMAPS 
Hypsographic information may be considered indispensable to most users of orthophotomaps. Current 
methods of obtaining this information from instruments in which profiling is done manually, as well as those 
instruments in which the profiles are produced automatically through the use of image correlators, are 
discussed. The deficiencies of height information derived from dropped lines, especially at the larger scales, are 
noted. Proposals are presented for improved systems of obtaining necessary height information. Three- 
dimensional interpretation of the orthophoto image, combined with the possibility of extracting precise 
vertical information on any point or feature of the terrain, is offered by the stereoscopic orthophoto technique 
developed at the National Research Council of Canada. The technique and equipment for compilation from 
stereoscopic orthophotos are presented. Although these orthophotos are produced on equipment still 
considered experimental, which affects speed of production and accuracy of the product, results obtained from 
large-scale mapping experiments are encouraging. Literature on cartographic treatment for orthophotomaps 
published during the last quadrennium is reviewed, with special emphasis on the different reproduction 
techniques for orthophotomaps in both large and small quantities. Experimental results of the amount of 
resolution transferred in the production steps of orthophotos are given. Applications of orthophotos as an 
image base in the production of interim map products or special products such as urban maps, coastal maps 
and charts, and airport obstruction charts are discussed along with the uses of orthophotomaps in standard 
map series at both large and small scales. 
22.  Neumaier, K. 
Austria 
AN INTERPRETATION EXPERIMENT 
Abstract not provided. 
52