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A COMBINATION DRAWING AND TRACING TABLE 
FOR USE WITH MULTIPLEX* 
by 
S.G. Gamble** 
The International Society for Photogrammetry is success- 
fully fulfilling a very important function through its Commission 
II by recording recent developments in stereo-plotters and other 
photogrammetrical equipment. Much valuable information can be 
gained from these meetings and the papers published by the 
Society will keep the capabilities and limitations of various equip- 
ment in true persepective. By bringing members up to date on 
the many types of equipment that are useful tools in this ever 
broadening field of photogrammetry, the Society will help to en- 
sure that the proper equipment is employed in the most economi- 
cal manner. With such information one should be able to avoid 
the mistake of either using an instrument on work beneath its 
capabilities or on work beyond its performance, the former being 
uneconomical utilization of equipment and the latter unsound 
photogrammetrical practice. 
For the mapping of areas that are already covered by good 
maps where the requirement is for large scales and greater 
accuracy, high precision plotters should certainly be used. In 
countries such as Canada, however, there is a great need for 
maps at a scale of 1:250, 000 and the information that can be shown 
at this scale of map can be extracted efficiently from air photo- 
graphs by simple equipment, and complete dependence upon pre- 
cision plotters would be unrealistic. In between these extremes, 
there is a place for plotters of intermediate precision, and multi- 
plex effectively fills a part of this need. This does not, however, 
rule out the use of high precision instruments for establishing 
wha 
* Presented to Commission II of the International Society for 
Photogrammetry at Stockholm, July 1956, with the permis- 
sion of the Acting Deputy Minister, Department of Mines and 
Technical Surveys, Ottawa, Canada. 
** Chief Topographical Engineer, Department of Mines and 
Technical Surveys, Ottawa, Canada. 
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