bugGNU Octave - Bugs: bug #42766, incorrect color patches for...


bug #42766: incorrect color patches for countourf with NaNs in data

Submitter:  None
Submitted:  Mon 14 Jul 2014 03:42:01 AM UTC
Category:  Plotting Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Incorrect Result
Status:  Confirmed Assigned to:  None
Originator Name:  Andreas Stahel Originator Email:  -email is unavailable-
Open/Closed:  * Open Release:  * dev
Operating System:  * GNU/Linux Fixed Release:  None
Planned Release:  None
* Mandatory Fields

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Thu 15 Dec 2016 06:11:26 PM UTC, comment #4: 

This issue is still present in Octave 4.2.0.

The code sample from comment #3 still gives an upper "line" that consists of several differently colored triangles.

Hartmut <hardy>
Sat 01 Nov 2014 08:45:20 PM UTC, comment #3: 

Thanks for the '-Inf' workaround.
It has proven useful in another case

Sometimes '+inf' is better.

Here is a case where neither '-inf' or '+inf' work.
(in bothsides-inf.png; the upper stripe should be in dark red)

[x, y] = ndgrid(0:10:100, 0:10:100);
data = x + y;
data(data > 150) = NaN;
data(data < 50) = NaN;
data(isnan(data)) = -inf;
c = contourf(x, y, data);

using +inf is worse (resulting in bothsides+inf.png).

John Hunt <huntj>
Sun 03 Aug 2014 05:25:28 PM UTC, comment #2: 

Ther is a woraround
Replace all NaN by -Inf and contourf() will produce the expected result

Andreas Stahel <sha1>
Mon 14 Jul 2014 04:37:35 AM UTC, comment #1: 

Confirmed.  This is almost certainly related to bug #37501.

Rik <rik5>
Group administrator
Mon 14 Jul 2014 03:42:01 AM UTC, original submission:  

For a visualization I use colored contour plots, with some data
being NaN. All versions of Octave I used showed servere
problems when multiple data points were missing
A comercial product produced the correct coloring.
See the enclosed, constructed sample code.

It might be a bug in Octave.
It might be related to bug #37501 and #35033



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Attach Files:

Attached Files
file #32352:  bothsides-inf.png added by huntj (103KiB - image/png)
file #32353:  bothsides+inf.png added by huntj (89KiB - image/png)
file #31711:  contourfNaNbug.m added by None (143B - text/x-objcsrc)


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  • -email is unavailable- added by hardy (Posted a comment)
  • -email is unavailable- added by huntj (Updated the item)
  • -email is unavailable- added by sha1 (Posted a comment)
  • -email is unavailable- added by rik5 (Posted a comment)
  • -email is unavailable- added by None (Submitted the item)

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    Follow 7 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2019-11-26 rik5 Dependencies- bugs #57310 is dependent
    2014-11-01 huntj Attached File- Added bothsides-inf.png, #32352
        Attached File- Added bothsides+inf.png, #32353
    2014-07-14 rik5 Dependencies- Depends on bugs #37501
    2014-07-14 rik5 StatusNone Confirmed
        Summaryincorrect color patches for countourf incorrect color patches for countourf with NaNs in data
    2014-07-14 None Attached File- Added contourfNaNbug.m, #31711

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