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Re: Iso-contours at maximum/minimum levels [message #64874 is a reply to message #64873]

Fri, 30 January 2009 07:36

pgrigis
Messages: 436
Registered: September 2007

Senior Member

Hi,

two points:

i) the 12 dots is perfectly fine. It is z that is svcrewed ;-)

I think that if you take a proper example,
you'll see a proper result.

a=dist(512,512)
a[300:400,300:400]=0
contour,a
contour,a,levels=0.001

ii) David is right, but I still think there's an
easy way to show the shape of the minimal surface:

ind=where(a EQ min(a))
b=a*0
b[ind]=1
contour,b,levels=0.5

or somehting like that

Ciao,
Paolo

David Fanning wrote:
> Jeremy Bailin writes:
>
>> Paolo's suggestion makes perfect sense... but then I tried it and I'm
>> befuddled. The minimum contour consists of just a few dots!
>
> Exactly, because of round-off errors, etc., there is nothing
> there, really, to "contour". I think the person who asked
> the question wants an imprint of the minimum value of the
> surface (within some epsilon, obviously). And I continue
> to insist this is *not* the same as a "contour".
>
>> There's something funny about how it's drawing the contour that gets
>> very confused by the abrupt change right at the minimum.
>
> I don't think it is confused. I think it is doing exactly
> what the programmer designed it to do. I think it is our
> thinking about the problem that is confused. :-)
>
> 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]

		Re: Iso-contours at maximum/minimum levels By: pgrigis on Fri, 30 January 2009 11:00
		Re: Iso-contours at maximum/minimum levels By: David Fanning on Fri, 30 January 2009 07:48
		Re: Iso-contours at maximum/minimum levels By: pgrigis on Fri, 30 January 2009 07:36
		Re: Iso-contours at maximum/minimum levels By: David Fanning on Fri, 30 January 2009 07:21
		Re: Iso-contours at maximum/minimum levels By: Jeremy Bailin on Fri, 30 January 2009 07:04
		Re: Iso-contours at maximum/minimum levels By: pgrigis on Thu, 29 January 2009 15:14
		Re: Iso-contours at maximum/minimum levels By: David Fanning on Thu, 29 January 2009 14:51
		Re: Iso-contours at maximum/minimum levels By: David Fanning on Thu, 29 January 2009 08:15
		Re: Iso-contours at maximum/minimum levels By: Gianluca Li Causi on Mon, 02 February 2009 04:14

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