(Comp.sys.handhelds)
Item: 2590 by dan at Apple.COM
Author: [Dan Allen]
  Subj: City DataBase for HP-48 (LONG: 40 KB)
  Keyw: cities,HP-48,navigation
  Date: Mon Apr 01 1991

The following programs generate random trips between cities
in a database.  The TRIPS command continuously generates trips until the
clear key is pressed.  It in turn calls CALCTRIP to display the
latitude, longitude, and elevation (in feet) of the two cities, followed
by the great circle distance in US miles, the difference in elevation,
and a rough approximation to the heading one would go in to arrive at
the destination city.

The database is large, containing over 1,000 cities.  They are all of
the airports in the Western states (Washington, Oregon, California,
Arizona, Nevada, and Utah), as well as a few other cities in the US,
like Chicago, New York, etc.

All of the information came from an FAA database.  Your own cities are
easily added, or these cities deleted.  In those cities that have
multiple airports, a single airport was chosen on a semi-random basis.

The final item displayed is an approximate time that it would take to
travel between the two cities.  I chose a speed of 40 mph which
compensates for the fact that the distance is great circle distance, and
to drive between the two cities, one must follow roads which are not
great circles.  If you wish to use this for flying applications, then
you could substitute a faster speed.  The 40mph figure does a pretty
good rough approximation of what it takes to drive at 60 mph.

A second version of TRIPS, called SLOWTRIPS, is also included when
memory is tight.  The fast TRIPS routine puts the list of cities on the
stack and picks them off of the stack, two random cities at a time.  It
is pretty zippy.  SLOWTRIPS uses the GET function to grab a list from
the city database and it is very slow.

This whole file is about 41 KB, so you must have installed some extra
memory to run it.  Of course 40 KB of this is the city database I have
included.  Omit those cities that are of no interest to you and you can
reduce the size of this immensely.

Another routine called BFIND allows a binary search to take place for a
given city name, with its data returned to the stack.  Calling BFIND
twice, with the source and destination names, leaves the information on
the stack so you can then call CALCTRIP to determine the distance and
rough time, course, etc.

The format for the cities is simple: it is a list composed of other
lists, one list per city.  The list is sorted alphabetically by city
name, so that the binary search works.  Each city has the following
information associated with it in this database:

        City name (string)
        Latitude (real)
        Longitude (real)
        Elevation (integer)

Enjoy!

Dan Allen
Apple Computer