I'm having some issues when trying to change the color of the contour lines:
The basic script is:
reset set isosamples 50 set samples 50 set xrange[-2:2] set yrange[-2:2] set contour surface splot '++' using 1:2:(exp(-($1)**2-($2)**2)) with lines
The contour lines start with
linetype 3, so there is an offset of 2 with respect to the surface grid.
When I change the first line type with
set linetype 1 lc rgb 'black'
the contour lines start with
linetype 2, the offset is only 1. Is this intended?
When I only want to change one of the contour lines to be black, but leave the other linetypes untouched, i.e. I have only the settings
set linetype 3 lc rgb 'black'
Theses settings are totally ignored, all line color are like in the default settings. What's going on here? I thought,
set linetype should change the default
linetypes, but then there shouldn't be a difference, whether I redefined them or not.
set linetype 1 lc rgb 'black' set linetype 3 lc rgb 'red'
works as expected.
linewidth settings are taken from the surface line settings. All other
linewidth settings are ignored. I agree, that it makes sense to have all contour lines with the same
linewidth, but they mustn't be forced to have the same
linewidth as the surface lines.
set linetype 1 lc rgb 'black' set linetype 2 lc rgb 'red' lw 3
doesn't affect the contour's
set linetype 1 lc rgb 'black' lw 2 set linetype 2 lc rgb 'red'
does, but also changes the surface properties.
I find some of these issues quite inconsistent, and this behaviour is not documented. Could you please comment on all questions, if the behaviour is intended, or if it's a bug? Afterwards I can submit a proposal for according additions to the documentation.