I’m still playing around with GMT to generate some maps. I’m not sure I’ve really got it figured out, but here is an attempt to draw a world globe with some of the great circles that connect me to the various stations that have received my WSPR beacon messages.
Addendum: Robert pointed out that I didn’t give a link to the GMT tools. Consider this to be the remedy. They are kind of a quirky set of tools that can be used to create very nice output in a number of different projections, but they aren’t the simplest to figure out. I first learned about them from the book Mapping Hacks which is well worth owning.