coordinate capture peripheral

From an 80s Royal Air Force recruitment video, a peripheral is shown and it is used to capture coordinates off a map, onto a computer, for the flight plan to be written on a casette, for loading on the combat jet's (a Panavia Tornado) navigation computer.

How did this coordinate capture peripheral work?

(I tried to google it, but I couldn't finding anything.)


1 Answer 1


This looks like a large digitizer board (a.k.a. digitizer, digitizing tablet, graphics tablet, and variations) with a map overlaid on it. They were very popular in CAD (computer-aided design) applications in the '80s and early '90s, and are, to my surprise, still available today. They are quite useful for any application which requires precise coordinate entry, such as tracing outlines of objects for machining, or, as shown here, inputting map coordinates.

The board has a fine wire grid inside it, and the cursor or pen creates an electrical field which is sensed by the grid. Depending on the resolution of the grid in the board, it can determine the coordinates of the cursor to a very high degree of accuracy. Modern ones work over USB, but older ones would use some form of serial connection to report the cursor's position.

It can sometimes be hard to find information on these devices, since, without knowing what to search for, your search results will be skewed toward modern graphics tablets and tablet computers.

More information is available from The Logic Group's Logic Trace Digitizing System page and their Digitizer Board page. Additional manufacturers' boards boards are shown at DigitizerZone.

(I have no affiliation to these sites; they're just ones I turned up when I searched.)

  • 1
    Those were the second generation devices. The first one I used worked off line and punched the coordinates to paper tape. The puck (with cross hairs and a magnifying lens) similar to the OP's picture contained permanent magnets, which attracted a jointed mechanical arm underneath the glass top of the table. The readout of the arm position was by rotary encoders on its joints. This might sound like it was designed by Rube Goldberg, but it retained its specified accuracy of better than 0.1mm for at least 20 years. The "wire grid" type of tablet that replaced it was nowhere near as accurate.
    – alephzero
    Commented Sep 20, 2019 at 13:21
  • … sadly, I can't remember the manufacturer's name - it was probably new in the early 1960s.
    – alephzero
    Commented Sep 20, 2019 at 13:26
  • @alephzero Ferranti-Cetec?
    – scruss
    Commented Sep 21, 2019 at 0:32

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