[Gnuplot-info] 2. Re: Question on Plots on Non-regular Grid (Lorenzo Isella)

[Gavin B. <gav...@ya...>]

Hi Lorenzo,

I don't have an answer to your question - your essentially plotting your data as a rectangular plot, with R and theta on the x and y axis. This is fine and a perfectly valid way of representing your data, but it seems to me that what you want is to plot your data on a cylinder. So the final image would be a coloured cylinder. While I haven't worked in cylindrical coordinates before, I know it is possible with gnuplot.... try looking at http://gnuplot.sourceforge.net/demo/world.html for some ideas....

I personally wouldn't use gnuplot to plot this data, but matlab using patches or even povray which is freely available and produces some beautiful results. Both of which will require writing a program to convert your data into essentially coloured tiles. But somebody on here might be able to do it much simpler in gnuplot - I'd be interested to see the solution!

Gavin.


Hello,
And thanks for your suggestion.
It seems there is a problem, though.
Somehow gnuplot does not understand that it is working on a cylinder
cross section.
If I try:

set dgrid3d 10,10
set hidden3d
set pm3d
splot "example.txt" u 1:2:3 with lines

where "example.txt" is the file containing the data as shown in the
email, what I get is a rectangular grid. Is it simply an artifact due
to the low number of grid points or am I doing something wrong?
Many thanks

Lorenzo









       
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