Can someone in ATC explain the blue dotted line. Doesn't seem to have any shape. The green half circle i assume is the airspace?
The blue line appears to be the flight path of the "brickyard 3329" which they decided to plot. The circle appears to be a range ring of about 20 miles centered on the airport. It maybe an airspace boundary but my guess is it's just there as a reference point. The video was rendered by feeding archived radar data though some software which recreates the look of the radar scope. It's not a direct recording of the/a radar scope per se. So there are elements that are shown that may or may not have been on the actual radar scope at the time of the incident.