Decca Roller Map Display

[djrm]

The map, as I understand it, was for fixed areas with the pointer that could include a pen to draw a trace of the route travelled.  Very popular wuth fishng trawlers who could lift the lid and and add an X where they had found good fishing on previous occasions.

There must have been loads of maps and it would be good to find one for it.

Gary

I had assumed this was an aviation device, I se the Decca system was used for both ships and aircraft too. Getting an actual map would be great, or even seeing what one looked like. D