Some spysat orbital constellation plots (KH-12 Keyhole, Lacrosse and IGS)
(see here for details on how the plots were made and additional plots)
This plot shows how the IGS satellites keep an eye on North Korea:
SatTrackCam Leiden (Cospar 4353) is an amateur satellite tracking station located at Leiden, the Netherlands. Using a camera it makes accurate positional measurements on satellites of interest, mostly classified satellites -i.e. spy satellites- in order to determine their orbits.