Building an early wartime combat information centre

What radar and equipment would an early World War II combat information centre use?

A rotating radar connected to a plan display could provide the two-dimensional contact picture needed for a CIC; a simple trace was insufficient in this explanation.

The answer makes the radar display the threshold for an early combat information centre. A simple trace on a screen does not provide the plotted picture needed to understand a tactical situation. A rotating radar feeding a plan display can provide a two-dimensional picture of contacts. That display gives position, without altitude, so it should not be read as a complete three-dimensional view.