I've written up another pm3d corners2color function. It works just as
the others, i.e.,
set pm3d corners2color rms
rms4 takes the root mean square of the four corners
The RMS has many physical interpretations . Later on, I may write a
similar function for standard deviation...
My field of research is computational (statistical) physics. I make
heavy use of pm3d to represent three variable systems. As such, more
corners2color functions will come in useful.
The patch I've attached here was generated as advised using diff -ur