I am using gnuplot 4.5.0 downloaded from CVS today (11/3). System:
2.6.18-274.el5 #1 SMP Fri Jul 8 17:36:59 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
I am plotting gridded data using pm3d map. Commands used:
> set pm3d map
> set palette
> splot 'dat' us 1:2:12
The column of data corresponding to x = 24.5 has all z values = 0 (column 12 is 0 for all x = 24.5). This can be verified by plotting without pm3d and looking at the 3D plot.
However, in the color map produced by splot, the column corresponding to x = 24.5 has different colors (not all 0). Instead of producing a column of a single solid color equal to 0, it has a variety of different colors/shades.
This is very frustrating since I had thought the data was wrong until I finally found gnuplot was the problem!
I am attaching the data file