NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.

To learn about what's going on, see About the Archive Site.

RE: Bug resampling field with Irregular2DSet to Linear2DSet

  • To: "Bill Hibbard" <billh@xxxxxxxxxxxxx>
  • Subject: RE: Bug resampling field with Irregular2DSet to Linear2DSet
  • From: "Ian Graham" <ian@xxxxxxxxxx>
  • Date: Tue, 29 Apr 2003 19:53:12 -0600
Thanks Bill, it works!

As for my data being weird, well<grin>, it doesn't seem it to me!  It
consists of measurements that are taken over as close to a perfect grid as
possible, but likely rotated and certainly with many gaps and offsets due to
physical obstructions in the field.  As for the larger sizes, I was enjoying
Curtis's DelaunayFast until I started getting triangulation errors.

I worry when you mention that co-linear points cause problems, because
almost all of my data is similarly co-linear, although often not orthogonal
to the axes.  That invites my implementing my  own triangulation and using a
CustomDelaunay that exploits this co-linear tendency, but that doesn't seem
trivial even in my near-gridded cases, and I still have to support the
general case.  I was hoping that in the medium-term I could use well-known
algorithms _that_work_ even if they're imperfect:  I'm not terribly fussy
how equilateral my triangles are, but I do care that the coverage is
complete and non-overlapping so that interpolation can work.  Can none of
the Delaunay algorithms guarantee this?

And Curtis, thanks for the DelaunayFast.  Unfortunately, I'm getting a fair
number of "Delaunay.finish_triang:  error in triangulation!" exceptions.
But fortunately it's fast enough that I can always try it first!

My apologies for the large attachment, I just never succeeded in reproducing
the problem with a smaller dataset.  It's just as well that it didn't make
it to the list.  I guess I should've written the data in binary form instead
of ascii.

Thanks again for your help!
Ian


  • 2003 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the visad archives: