| IDL and 3D scattered data [message #15589] |
Fri, 28 May 1999 00:00  |
T Bowers
Messages: 56
Registered: May 1998
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Member |
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Uh oh...
I thought that IDL could help me out with 3D
oceanographic data visualization. Turns out it
just ain't so. There doesn't seem to be a way to
interpolate scattered 3D data in IDL. Anybody know
of a routine(s) that'll do what triangulate/trigrid
or sph_scat will do but in 3 spacial dimensions? BTW,
when I say 3D scattered data, I mean *real* 3D
scattered data. That means 3 independant variables
and 1 dependant variable, as in x,y,z,f(xyz). E.g., I have
data in the form:
Longitude Latitude Depth Temperature
-84.3333 22.6105 0.0 24.2
-84.3333 22.6105 2.7 24.0
-84.3333 22.6105 5.0 23.2
-84.3104 22.6384 0.2 24.2
-84.3104 22.6384 2.2 23.2
-84.3104 22.6384 4.8 23.1
-84.2999 22.6480 0.1 25.1
etc,
etc.
For some reason alot of scientists and scientific packages
refer to 2D plots that are rotated into 3D space
as 3D stuff (surface, shade_surf, and David Fanning's
example of using PlotS,...,/T3D in his book are good
examples. Great book, BTW!). It may be a nit pick, but
certainly no one would view a graph of f(x)=x as a 2
dimensional graph.
Sooo... any thoughts on my rantings? Any pointers to
some 3D interpolation stuff?
Thanks,
Todd
--
Todd Bowers
PSI-MSAAP Bldg. 9121
Stennis Space Center, MS
tbowers@nrlssc.navy.mil
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| Re: IDL and 3D scattered data [message #15666 is a reply to message #15589] |
Tue, 01 June 1999 00:00  |
landsman
Messages: 93
Registered: August 1991
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Member |
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In article <7iui0a$c9s$1@ra.nrl.navy.mil>, "Todd Bowers" <tbowers@nrlssc.navy.mil> writes...
> So , does anybody know of a 3D Delaunay tetrahedralization
> function?
> Anybody also know how to implement natural neighbor interp.
> based on the tetrahedralization?
>
> Thanks,
> Todd
Todd,
You might try one of the three routines written by Joop Schaye,
based on the 3-d interpolation schemes discussed in R.W. Hockney
and J.W. Eastwood, Computer Simulations Using Particles (New York:
McGraw-Hill, 1981).
NGP - Nearest Grid Point interpolation (lowest order)
CIC - Cloud in Cell interpolation (higher order)
TSC - Triangular Shaped Cloud interpolation (highest order)
These three procedures are available in the IDL Astronomy Library
ftp://idlastro.gsfc.nasa.gov/pub/pro/math
--Wayne Landsman landsman@mpb.gsfc.nasa.gov
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