Extracting tracks of individual planes from recorded radar data

[DaveReidUK]

Re Dave's mentioning of "editor", are you referring to a human putting the graphic together manually and while doing so ommitting the second loop of the figure of eight?

No, simply that it appeared on D K-M's Twitpic:

http://twitpic.com/csse7a

I doubt he would have done any manipulation of the image, which looks like it has originated from one of the flight-tracking websites.