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Groups > comp.graphics.apps.gnuplot > #4023

Re: contour lines have points

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On Tue, 31 Jul 2018 09:42:04 +0200, Karl Ratzsch wrote:

> Am 31.07.2018 um 07:05 schrieb Jörg Buchholz:
>> I would like to have points where the measuring point are, they are at
>> the surface not at the contour lines.
>> 
> 
> But they aren't, those are the interpolated points from dgrid3d!
> 
> I agree it makes little sense to have points on the contour, except to
> show the principle of how they are generated. Perhaps (and the key
> implies that was intended, although that's probably an accident) they
> should be omitted by default.

I can't think of any case where it makes sense to use "linespoints" for
contours.  Can you point to an example of such a plot?

> But you also can't give e.g. a different linewidth to the contour and
> the 3d grid. You'll have to save the contours to a data block via "set
> table $contours", switch off contour generation, and then (re)plot the
> contours after making the pm3d plot via

That's more complicated than is necessary.  You can separate the 
contour line characteristics from the surface directly in the splot command

     set contour base
     set cntrparam ...
     set pm3d explicit depth noborder ...

     splot $DATA with pm3d nocontour, $DATA with lines nosurface lw 2

This gets you a pm3d surface with no contour or grid lines together
with a contour plot at the base.  
 
>   replot for [i=1:5] $contours index i us 1:2:(0) lc i lw 2
> 
> (assuming 5 contour lines and the base to be at z=0).
> 
> Anyway if you want to see your original datapoints instead of the
> interpolated dgrid3d points, you have to add them on top of the pm3d
> surface and contours.
> 
> I think the graph you envision is just a bit too complicated to be made
> by just one single plot command. ;-)

It is straightforward in gnuplot 5.   The save-to-a-file-and-replot
workaround is no longer needed.

	Ethan

> 
> Best, Karl

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Thread

contour lines have points Jörg Buchholz <bookwood4new@freenet.de> - 2018-07-30 15:13 +0200
  Re: contour lines have points Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2018-07-30 21:10 +0200
    Re: contour lines have points Jörg Buchholz <bookwood4new@freenet.de> - 2018-07-31 07:05 +0200
      Re: contour lines have points Karl Ratzsch <mail.kfr@gmx.net> - 2018-07-31 09:42 +0200
        Re: contour lines have points Ethan Merritt <sfeam@users.sf.net> - 2018-07-31 20:08 +0000
          Re: contour lines have points Jörg Buchholz <bookwood4new@freenet.de> - 2018-08-01 07:56 +0200
        Re: contour lines have points Jörg Buchholz <bookwood4new@freenet.de> - 2018-08-01 07:42 +0200

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