s.surf.tps dmin

[James Darrell McCauley]

is the dmin parameter in s.surf.tps there for computational efficiency
(to thin out points), or is there some void in my understanding of the
algorithm?

I have run a series of experiments wherein I delineated a path through
an analytical surface. The path reflects traverses made by some sort
of vehicle (I included "turnarounds" at the end of each traverse). I
looked at several different sampling frequencies (density of points)
along this path and minimized the MSE for each sample set to determine
optimum tension/smoothing parameters. I have found that at the two
highest frequencies, the MSE increases substantially.  This seems
counter-intuitive. Any guesses here?

--Darrell