Plotting a surface from points in the space

[Luc4]

Hi! Is it possible to plot a colored surface taking points (x, y, z) which are not in a grid? They are taken from pdetool, so they covers a surface but are not in grid format. I can only plot them with points in gnuplot. Is it possible to interpolate them with a surface? I tried interp2, but it needs points to be in a grid.
Thanks! Bye!

[David Bateman]

Luc4 wrote:
> Hi! Is it possible to plot a colored surface taking points (x, y, z) which
> are not in a grid? They are taken from pdetool, so they covers a surface but
> are not in grid format. I can only plot them with points in gnuplot. Is it
> possible to interpolate them with a surface? I tried interp2, but it needs
> points to be in a grid.
> Thanks! Bye!
>  

Try

help griddata

or

doc griddata

D.

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[Carlo de Falco-2]

On 11/gen/08, at 16:34, Luc4 wrote:

> Hi! Is it possible to plot a colored surface taking points (x, y,  
> z) which
> are not in a grid? They are taken from pdetool, so they covers a  
> surface but
> are not in grid format. I can only plot them with points in  
> gnuplot. Is it
> possible to interpolate them with a surface? I tried interp2, but  
> it needs
> points to be in a grid.
> Thanks! Bye!

Hi Luca,

you might want to take a look at the FPL package in octave-forge,
it plots data on triangular grids defined by (almost) the same data  
structure
as that used by pdetool.

for example "FPL2pdesurf (msh, z)", where msh is a structure with the  
usual p,e,t fields of a pdetool mesh, does what you want.

if you do not want to install additional packages, a solution could  
be using the "trimesh" command which has been moved to core octave in  
recent versions, but this would plot just the grid without a coloured  
surface ( the equivalent of pdemesh rather than pdesurf)

Carlo
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