2D Scatter Plot with Variable Size and Color

[Andy]

Hi, I am struggling with the necessary commands to achieve the type of
graph that I need. Basically I want to create a 2D version of one of
these:

http://gnuplot.sourceforge.net/demo_4.2/rgb_variable.html

I have a data file with lines like:

10 20 3
5 30 6

The first two values are x and y. Third value is size. I want the RGB
value to be calculated from x and y. Here is my script:

set terminal png nocrop enhanced size 420,320
set output "graph.png"
set title "Measurements"
rgb(r,g,b) = int(r)*65536 + int(g)*256 + int(b)
plot "data" using 1:2:3:(rgb($1,$2,0)) with points pt 7 ps variable lc
rgb variable

When I run it (gnuplot 4.2, Debian Sarge), I get:

"scatter.gnu", line 6: Too many using specs for this style

Any ideas? Help would be greatly appreciated!

regards, Andy

[Ethan Merritt]

In article <1184953504.4...@z24g2000prh.googlegroups.com>,

Yes. Your commands are correct, and they work fine in the CVS
version of gnuplot. However, the use of variable color in 2D plots
was a last minute extension that didn't quite make it into the
4.2.0 release. It will be in the 4.2.1 incremental release,
expected in the next month or so.

As a work-around, in most cases it is possible to use a 3D plot with
"set view map" and giving a dummy Z coordinate. So your command
would become:

splot "data" using 1:2:(0):3:(rgb($1,$2,0)) \

with points pt 7 ps variable lc rgb variable

--
Ethan A Merritt

[Andy]

Thanks Ethan - that worked great!

Andy