[Gnuplot-bugs] Possible gnuplot bug

[Zoran M. <mi...@sa...>]

Dear Sir/Madam,

   I have found an anomaly in gnuplot when trying to plot contours with 
the "splot" command.  Below I describe the problem, which I have 
isolated to a small section of code.  The problem shows up both with 
version 4.0:

         Version 4.0 patchlevel 0
         last modified Thu Apr 15 14:44:22 CEST 2004
         System: Darwin 7.7.0

and with version 3.8j:

         Version 3.8j patchlevel 0
         last modified Wed Nov 27 20:49:08 GMT 2002
         System: Darwin 7.7.0

   The attached text file, "bad_contour" has data for a single contour.  
I have extracted it from one of my contour plots after much debugging.  
(It was generated with gnuplot.)

The following command plots the contour correctly:

plot "bad_contonur" w l

The following command DOES NOT plot the contour correctly:

splot "bad_contonur" w l

You can see that the contour folds over itself at every segment.  The 
connectivity of points in the (three) segments of this contour is not 
treated correctly.  Plotting the contour without connecting the lines, 
as in:

splot "bad_contonur"

shows that the points in the contour are OK, but they do not get 
connected properly when a line is used to join them.

   Please let me know if you have any questions.  Thanks for developing 
and maintaining a very nice and useful program.

   Best regards,

   Zoran Mikic

   email: mi...@sa...