named-places.txt
----------------

Every officially named place in the U.S., one per line. The format is:

  8 digit unique code for the place
  2 character postal abbreviation for the state
  the name
  its population
  its area in square miles
  its latitude north
  its longitude east
  an up to 5 digit reference number for its representative road intersection
  the distance in miles between the centre of the place and that intersection.


intersections.txt
-----------------

Everywhere in the U.S. that two major roads meet, or that one major road has
a notable change of direction. One per line. The first line is considered to
be line 0 and does not contain useful data.

  longitude
  latitude
  distance from nearest named place
  what that named place is, state then name.


connections.txt
---------------

The roads (and other things) that run between those intersections, in no particular
order. Each line contains five space-free items:

  the official name of the road, or "?" if it hasn't got one
  what kind of road it is, as a three character code
       the only really significant part of this is the first letter - F indicates
       that it is a ferry crossing and not a road at all.
  intersection A
  intersection B
       the road connects A to B. A and B are line numbers (counting from 0) in
       the intersections.txt file
  the length of this section of road, in miles.