looking for task to do Delauney triangulation

rfinger wrote on Jan 30, 2008

Hi - does anyone know if IRAF has a set of tasks for converting a list of irregular-spaced coordinates into a grid/image? IDL does this using TRIANGULATE and TRIGRID. Does IRAF have some equivalent? Thanks!

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Mike Fitzpatrick wrote on Jan 30, 2008

The SURFIT task will fit a polynomial surface to a set of points and can create an image, but there's nothing that tesselates the surface the way you describe (AFAIK).

-Mike

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James Turner wrote on Jan 30, 2008

I did something like this in IRAF using "IDBVIP" and other associated ForTran subroutines, obtained from Starlink PDA library (but originally from TOMS). The result is a smooth piecewise interpolation, rather than a Delaunay triangulation.

http://www.starlink.rl.ac.uk/star/docs/sun194.htx/sun194.html

This involves writing your own (relatively simple) IRAF task in SPP, however, and linking to the library. My task was for 3D datacubes rather than simple images.

Cheers,

James.

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James Turner wrote on Jan 30, 2008

Actually, if you're OK with a smooth surface then it would be easier just to use surfit as Mike suggests, unless the idea of the tessellation is that you want to interpolate the original points rather than approximating them. I *think* IDBVIP will give you back the original values whereas surfit may not.

Cheers,

James.

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Last post on Jan 30, 2008