Re: [Gnuplot-info] Help with plotting 4D data

[Andy M. <and...@gm...>]

Actually I'm not sure if the plots are coming out correctly.  I
thought they were, but looking at the data there is a particular
segment that doesn't plot correctly.  I don't really want to list the
full data so I'll try to abbreviate...

a whole load of segments like this (where my data is constant)...

1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000
1.000000 0.000000 1.000000 1.000000

then..

1.000000 0.004990 0.990020 1.100000
1.000000 0.008982 0.982040 1.100000
1.000000 0.014970 0.970060 1.100000
1.000000 0.019960 0.960080 1.100000
1.000000 0.024950 0.950100 1.100000
1.000000 0.029940 0.940120 1.100000
1.000000 0.034930 0.930140 1.100000
1.000000 0.039920 0.920160 1.100000
1.000000 0.044910 0.910180 1.100000
1.000000 0.048902 0.902200 1.100000

1.000000 0.008982 0.982040 1.200000
1.000000 0.019960 0.960080 1.200000
1.000000 0.029940 0.940120 1.200000
1.000000 0.039920 0.920160 1.200000
1.000000 0.048902 0.902200 1.200000
1.000000 0.059880 0.880240 1.200000
1.000000 0.069860 0.860280 1.200000
1.000000 0.079840 0.840320 1.200000
1.000000 0.089820 0.820360 1.200000
1.000000 0.099800 0.800400 1.200000

etc.

the 'x' value doesn't change till a bit later.  (so at the moment the
surface is moving purely in the yz plane)  It seems as though none of
this data gets plotted until the x axis starts moving.

Now, I'm sorry if I get a little confused reading the documentation
but I end up getting a little lost.  It does warn me about doing this,
but just mentions care should be taken.  Is this a fundemental
problem/limit with Gnuplot?  The xyz data is generated by a function
(the 4th column with a hidden 5th variable - generating the 10 lines),
so I can't guarentee the scaling or anything.

Hope someone with a bit more experiance can walk me through this one...

Thanks,

Andy.


> On 6/15/07, Hans-Bernhard Br=F6ker wrote:
> > Andy Main wrote:
> >
> > > What I did is create two data files, one for the surface position dat=
a
> > > in the form:
> > [...]
> > > and another one the same for the colour data, but with the z column
> > > replaced by p
> >
> > That was the wrong idea.  You should just have put the 'p' (and 's')
> > column in the same file as x, y and z.  gnuplot can pick any three or
> > four columns out of a multi-column data file and use them as plot
> > coordinates.
> >
> > Read 'help datafile', 'help pm3d' and 'help splot using' thoroughly, an=
d
> > you should be able to figure out how to get the plot you need.  Pay
> > particular attention to the concept of grid data.
> >
>
> Yes, I was just in the process of posting back to the list.  I thought
> I read that the data needed to be in triples, but a nice coffee fixed
> this for me.  Its amazing how you can tie yourself in knots for no
> reason!
>
> Thanks for your help,
>
> Andy.
>