Accuracy checks of the comparator can be performed automatically and the time 
required for this check is a small fraction of the time required using conventional 
techniques. 
Dr. David Makow [13], National Research Council of Canada, has reported on a novel 
system for linear measurement. He calls it: *LINCAP — A Device for Precise Measurement 
of Length." 
Dr. Makow states that the LINCAP is a novel linear capacitor system to measure length 
or displacement with an expected accuracy of better than one micrometer and 
repeatability of one third of one micrometer, over a range of 25 centimeters, or more. The 
reading of the position can be obtained either with an automatic bridge which gives rapid 
digital display, or by manual balance. The reading is recoverable after power failure. There 
is no limit on the speed of displacement. 
The applications of the LINCAP are expected in photogrammetry, the machine tool 
industry and many research areas such as spectroscopy, microscopy, astronomy, and 
nuclear physics. 
Professor Dean C. Merchant of the Ohio State University, has just announced (Feb 72) a 
mensuration development that should be of interest to all who are bound by budget 
limitations. He describes this new instrument in a paper he has just submitted to 
Photogrammetric Engineering entitled, “The ‘P CATS’ A Stereocomparator of Novel 
Design (Point—Comparator and Transfer System)." 
In this novel design, two Leitz microscope stage comparators were modified to rest 
directly on the diapositives. A Bausch and Lomb Zoom 95 is used for viewing. The basic 
accuracy is estimated to be better than two micrometers for each axis. 
P-CATS, originally developed for special field applications, may now also find 
applications in both research and education. In one mode of operation, it is possible to 
select and measure the image, and record and analyze the coordinates, for all images of a 
given object space or terrain point. Another mode finds application to the transfer of 
control from a high flown block of photography to low flown photography intended for 
use in map compilation. Refinements, such as the addition of analog to digital encoding 
devices, may offer the P-CATS concepts as an attractive alternative application for 
production measurements. 
Again in the category of making maximum use of a limited budget, the San Antonio 
Field Office of the U.S. Army Topographic Command reports a development which 
extends the capability of the C-8 Stereoplanigraph ( XC8 System). 
A stereoplanigraph has been equipped with H. Dell Foster Company line encoders and 
digitizing unit (RSS-400). Data output is provided by a UNIVAC 1710 card punch unit 
interfaced with the digitizing unit. The line encoders are mounted directly on the x, y, z, 
moving parts of the main instrument frame. This type mounting does not depend on 
measuring the rotation of the lead screws but measures the actual line track movement of 
X, y and z. The instrument viewing system has been supplemented with zoom-type oculars, 
providing a maximum system enlargement up to 32X. Interfacing can be effected with 
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