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Re: Contouring binary data [message #2110]

Thu, 02 June 1994 03:55

steinhh
Messages: 260
Registered: June 1994

Senior Member

In article <hahn.7.00131ADF@hrz.th-darmstadt.de>, hahn@hrz.th-darmstadt.de (Norbert Hahn) writes:
|> Hi all,
|>
|> I have a matrix with binary data, that is the elements contain either zero or
|> one (or some other numer). If I convert the matrix from bytarr to fltarr and
|> call contour I get some but not all contour lines. Some of them are double
|> or triple lines. When I add ,levels=[0,1] I get single lines but miss even
|> more lines.
|>
|> I guess, IDL assumes some analogue data and tries to find a "slope" or
|> a "gradient" but fails to get all non-zero elements.
|>

If the matrix is, say, 10x10, try:

IDL> contour,congrid(data,200,200),levels=[0,1]

This avoids the problem with IDL interpolating between pixels.

|> The contour lines IDL returns are rather jaggy. How to smooth these lines ?

With the above method, they aren't *smooth* (they're quite square, in fact),
but I think they should be....

Stein Vidar Haugan
Institute of Theoretical Astrophysics,
University of Oslo,
Norway

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[Message index]

		Re: Contouring binary data By: steinhh on Thu, 02 June 1994 03:55
		Re: Contouring binary data By: sterner on Fri, 03 June 1994 09:48

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