Everyone knows that in the late game, the best way to reveal the map is ... to spam hundreds artillery shells all around.
So, why not have a shell dedicated for this?

This shell acts both as a mobile radar and as a light emitting flare in flight, and on landing, creates a stationary radar and light that last for a limited time.
Radar range settings and lifetime are configurable.
And while damage is barely there - it is affected by quality, as quality directly affects radar range.