gnuplot contour line color: set style line and set linetype not working

Question

I am plotting data as described in a previous Stackoverflow question: gnuplot 2D polar plot with heatmap from 3D dataset - possible? Mostly it is working well for me, and I

Answer 1

As a quick and dirty but easy solution, I sometimes relate all to only a single color:

set for [i=1:8] linetype i linecolor 0