(Click to embiggen)
Apart from the two outliers of recent Cambridge sabbaticals and friends from the 1980s International Astronomical Youth Camps, it's quite revealing of the gap between work and life, or business and pleasure. My Irish relatives are up at the top and my colleagues at my current employer (and my contacts in South Sudan) are as far away from them as possible.
Then there's a very telling gulf between a) sf fandom, and my educational peers (note how my grammar school friends divide into two cliques, basically the large group on the left are those who I was not as close to as the smaller group on the right); and b) my professional/political contacts, with Ulster politics loosely connected to schoolfriends, and Lib Dems loosely connected to Cambridge friends. Then we gradually work through degrees of foreignness and personal history - NDI, who I worked for 1997-98; ICG and other Balkan contacts, reflecting my 1999-2006 work; and finally my current job. There are a few geographical concentrations there as well, South Sudan (as already mentioned), Banja Luka (where we lived in 1997-98), the Turkish Cypriots with whom I was closely engaged in 2007-10.
This doesn't capture the full picture - there are obviously some nodes of connection between the various networks, and the links between fandom and the Lib Dems are more intense than appears here (as you would expect). But I'd better stop playing with it now, I am getting addicted...