Diagram for diplomatic relationship (war / alliance ...) like sdl2 client
The sdl2 client has a very interseting diplomatic report with nations on a circle, and colored links between them according to their relationships.
Something alike can be automagically done using graphiz library, which allows to weight distance, and tries to group/separate thing (maybe it is used for F6 science vue ?)
I made some test from saved game of scenario Europe1900 , turn 0 and turn 20
nothing else is shown
(i attach the script i made to genarate png from .sav.xz)
Other vues can be interesting too.
i like neato (generated by the script too), which gathers allies , and put enemies away