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Re: Problem with Polar_contour [message #62165 is a reply to message #62083]

Mon, 25 August 2008 17:09

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

tarequeaziz@gmail.com writes:

> why do we need to use 'triangulate' procedure to draw a polar_contour
> plot?

Because contour expects a rectangular Cartesian grid, and
you want to pass it something else, entirely. Thus, you are
going to have to re-grid your data to display it in this new
way. I would guess the polar points are causing you grief.
Probably all these spherical triangles are collapsing to a
point and appear to the triangulation algorithm to be co-linear.
It is a common problem, as you will see if you search the newsgroup
archives for "co-linear".

> please excuse my ignorance regarding this. because right now it
> seems like this is the last bone of contention. Triangulate is
> standing between me and the solution.

You may have to try some other way of gridding your data instead
of letting IDL attempt to solve the problem. IDL procedures exists
to help you do this. (MESH_DECIMATE, for example, helps to get
rid of overlapping vertices in the data.)

> BTW...have u noticed the uncanny resemblance between 'strangulation'
> and 'triangulation'....??

Not until just recently. :-)

I have a son who sometimes asks me to edit one of his papers. Then
he ignores my good suggestions and re-submits the paper to me for
further editing, and I make the same good suggestions (usually
concerning the difference between "there" and "their"), etc. This
conversation is beginning to remind me of that. :-)

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		Problem with Polar_contour By: tarequeaziz on Mon, 25 August 2008 12:46
		Re: Problem with Polar_contour By: David Fanning on Mon, 25 August 2008 17:09
		Re: Problem with Polar_contour By: tarequeaziz on Mon, 25 August 2008 16:44
		Re: Problem with Polar_contour By: David Fanning on Mon, 25 August 2008 16:03
		Re: Problem with Polar_contour By: tarequeaziz on Mon, 25 August 2008 15:46
		Re: Problem with Polar_contour By: David Fanning on Mon, 25 August 2008 15:36

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