RE: mapping z-values as point colors onto 2D plot
Hallmarc
Any help with this is much appreciated. I have a 3 column data file
that I would like to plot in 2D, with the 3rd column of the row
representing the color (within a spectrum) of that point. I've tried
a few things, including splotting with pm3d, but I can't seem to get
the thing that I want. This seems quite simple, and I think I just
haven't worked with Gnuplot long enough to get the fundamental
concept. Feel free to berate me, because I've read a whole lot of the
manual but can't figure this out.
Regards,
Marc
Ethan Merritt
Hallmarc <mchi...@gmail.com> wrote:
>Hi everyone,
>
>Any help with this is much appreciated. I have a 3 column data file
>that I would like to plot in 2D, with the 3rd column of the row
>representing the color (within a spectrum) of that point. I've tried
>a few things, including splotting with pm3d, but I can't seem to get
>the thing that I want. This seems quite simple, and I think I just
>haven't worked with Gnuplot long enough to get the fundamental
>concept.
Maybe:
set view map
splot 'data' using 1:2:3 with pm3d
If that's not it, then you need to explain more clearly what
you are aiming for.
--
Ethan A Merritt
Hallmarc
> In article <1193247108.148779.97...@i13g2000prf.googlegroups.com>,
>
> Hallmarc <mchiar...@gmail.com> wrote:
> >Hi everyone,
>
> >Any help with this is much appreciated. I have a 3 column data file
> >that I would like to plot in 2D, with the 3rd column of the row
> >representing the color (within a spectrum) of that point. I've tried
> >a few things, including splotting with pm3d, but I can't seem to get
> >the thing that I want. This seems quite simple, and I think I just
> >haven't worked with Gnuplot long enough to get the fundamental
> >concept.
>
> Maybe:
> set view map
> splot 'data' using 1:2:3 with pm3d
>
> If that's not it, then you need to explain more clearly what
> you are aiming for.
> --
> Ethan A Merritt
Unfortunately, there's something I'm not understanding about pm3d:
gnuplot> splot "socks.dat" using 1:3:4 with pm3d
Warning: Single isoline (scan) is not enough for a pm3d plot.
Hint: Missing blank lines in the data file? See 'help pm3d' and
FAQ.
socks.dat is a file with several hundred thousand rows, four columns
(column 2 is not used), and no breaks between rows. I want gnuplot to
plot column 1 on the x axis, column 3 on the y axis, and column 4
needs to be the color of the point at that (x,y) coordinate. The
colors range from 0 to 4500. The top of the data file has a few
comments (#), a single blank line, then the rest of the data.
Any ideas?
Hans-Bernhard Bröker
> Unfortunately, there's something I'm not understanding about pm3d:
>
> gnuplot> splot "socks.dat" using 1:3:4 with pm3d
> Warning: Single isoline (scan) is not enough for a pm3d plot.
> Hint: Missing blank lines in the data file? See 'help pm3d' and
> FAQ.
>
> socks.dat is a file with several hundred thousand rows, four columns
> (column 2 is not used), and no breaks between rows.
... which means it doesn't describe any surface, so pm3d can't plot it
as a coloured surface. Looks like what you really want is a plot of
coloured points, i.e.:
set view map
splot 'data' u 1:2:(0.0):3 with points palette
Either that, or you should insert the missing breaks into the data file.
Hallmarc
wrote:
That did the trick, thanks! I guess the third coordinate of 0.0 just
basically push everything up against a 2D plane...excellent.
