s.surf.tps (GRASS4.1.5 ?) and Linux

Pat Morrow pmorrow at maildrop.srv.ualberta.ca
Mon Mar 25 07:00:00 EST 1996

This note is concerning Kang's release of ELF binaries
of GRASS for Linux.
One of my users recently  started (or trying) using the
alpha/garden routine s.surf.tps.  At least on our site,
this routine is worse than useless.  My users first attempt
was on a fairly large data set (20,000 points: combine trajectory
data), and the only response was floating point exception.
Working with small data sets (less than 400 points), with no
mask file, I can get s.surf.tps to ``surface'' 1, 2, 3, or 6
data points out of 347.  All other points are ignored for
being out of the region (even thought the site list file
shows them to be in the region).  If I somehow stumble across a
set of parameters (dmin, tension, smooth, segmax, npmin) that
will surface through 6 points, and immediately re-run s.surf.tps
with EXACTLY the same parameters, it only surfaces through 3 points.
This seems likely to be a problem of using some value somewhere
in s.surf.tps BEFORE it is set.
  I am off to moon to get source, in an attempt to track down this
problem.  If anyone else tracks down the problem, please let me
Gordon Haverland, P.Eng.
Alberta Agriculture
Precision Farmining Project
ghaverla at freenet.edmonton.ab.ca
goddard at gpu.srv.ualberta.ca

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