Question

I’m trying to make a map with pm3d, but there are several “white spots” where the z-value exceeds the set zrange. However, when I try to change the zrange scale I see no difference in the plot.

Here’s the script I’m using:

set term postscript color
set output 'contour.ps'
set size ratio 1
set xrange[-15:25]
set yrange[-15:25]
set zrange[0:200] <------- Changing this range does nothing!
set pm3d map

splot 'format.out' using 2:3:(sqrt($4*$4 + $5*$5 + $6*$6 + $7*$7 + $8*$8 + $9*$9)) with pm3d

If I change anything else in the script (say, xrange) I can see the effect in the plot.

Any suggestions?

Also, why is the default zrange set so that some z-values are outside the range? Is there a way to change this default so that it always includes all data?

Thanks!

Answer 1

In this specific case, my data did not have enough space between columns, so when numbers became large the columns started overlapping and numbers became enormous. If, for example columns are defined to be 5 spaces wide, then the data

123  987

is fine, while the data 12345 and 98765 look like this:

1234598765

and become joined into a single data point, which gives a number that’s outside of any reasonable range. I don’t know why gnuplot doesn’t warn about two columns being compressed into one…

Also, as mentioned in the comments, changing the cbrange did increase the z range, but of course that didn’t help see the several points that were far outside any reasonable range due to the joining of columns.