At 18:31 5/11/2000, Andrew Grebneff wrote:
>  I'd find one useful both in the van (speedo)

Andrew, I don't think you'd find it a satisfactory speedometer for a car --
it doesn't measure speed directly at all, just takes successive positions
and integrates them over a period of time to produce a moving-average
speed.  Every time you turn your vector changes, and the displayed speed
drops because you're now averaging vectors in multiple directions and so
forth.  Worst case, I could easily imagine it displaying a speed of zero
while you went in tight circles at 30 mph.  All perfectly legitimate from a
navigation standpoint, but...

david
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"