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From: Ethan A Merritt <sfeam@users.sourceforge.net>
Newsgroups: comp.graphics.apps.gnuplot
Subject: Re: problems with splot of equation in 3D as a plane
Date: Tue, 20 Jan 2015 10:52:54 -0800
Organization: gnuplot development
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Karl wrote:

> Am 20.01.2015 um 06:40 schrieb seb.leeb@gmail.com:
>> Hi guys,
>> 
>> i need to do a gnuplot of a plane in 3D. I have the equation of the
>> plane. The problem is that the plane is nearly vertical. How can i adjust
>> the output of gnuplot to "rasterize" my plane in z-direction properly
>> 
>> My code:
>> set zrange[100:170]
>> set isosamples 200
>> splot [0:140] [0:100] (-0.00304622*x--0.999983*y-39.7027)/(-0.00491253)
>> with lines
>> 
> 
> (do you also get that one strange line in your plot? I guess you´re
> testing the numerical precision here.)
> 
> (don´t set the x/y axis ranges in the plot command. that´s widely
> regarded as "bad practice" ;-))
> 
> You could first plot to a table using a stongly reduced yrange (so you
> don´t get a billion points outside of the desired zrange), and then plot
> that tabulated data.
> 
> set sample 20; set isos 20
> set table $data
> set xr [10:12]; set yr [4:5]
> splot x*y
> unset table
> 
> set xr [0:40]; set yr [2:8]
> splot $data using 1:2:3 w l
> 
> If you don´t have gp50, simply replace $data by a file name.
> 
> Another possibility: Use parametric mode, and change the u/vrange.
> 
>  Karl

Or if the plane is supposed to contain some information
(contours? heat map?) you might want to create it first as an
image file and then map that into 3D as in plots 5/6/7 in
this demo:

	http://gnuplot.sourceforge.net/demo_4.6/image2.html

  Ethan