Re: Iso-contour radar
Wandering back decades, literally, 'Contour' was a term coined by the ECKO company, a British pioneer of Airborne Radar. It was a mode that was Pilot selectable that, when selected, inverted the video signal of the return above a certain strength, giving the Pilot an indication of the strongest return, similar to the red or magenta colouring on more modern colour radars. I don't know when it started being used, but the Comet and the 1-11 both had ECKO monochrome radars with contour.