This isn't really a Plan 9 question at this point, but since we've been talking about 2e a bit:

2e included a program road(7), which allowed you to explore a US map database. It has a neat property where you can highlight individual features via regexp match. You could have a map containing only selected roads (say you wanted to show only the Interstates going into your city).

road(7) never got updated after 2e, and I don't know how to recreate the Tiger database it pulled from, regardless.

Anyone know of anything, on any platform, which does something similar? Show only selected elements on a road map?