(UPDATED) Where are the observers? A map

Mid-June twilight starts very late, and generally I have not been observing the past 3 weeks due to that, as most interesting objects make passes well after midnight currently (and I need my sleep).

While exploring and practising with some simple GIS/mapping software I might start to use for my work, I made the map below. It shows you where the 20 most active observers regularly contributing position observations to satobs.org are located (the map was created with MicroDEM).

(click image to enlarge)

I also plotted my own two station positions on a combination of SRTM elevation data and a Landsat image. Cospar 4353 is my regular station and is in the centre of Leiden as you can see. My outpost station Cospar 4354 is in the polders to the east of Leiden, just south of the Rhine. (I exaggerated the relief by a factor 5 to better show the coastal dunes)

(click image to enlarge)