Use the contour filter to display isolines#
Add a contour filter
Chose the variable, you want to contour by, use the red x to get rid of the default contour level, use the scale icon (below + and -) to create a number series, (see below), finally select the levels
100 and the
0 and use the
+ to add
50 levels below them.
Adjust the line width to
5 by searching for
line in the search box in the top and then adjusting it.
BrBG as colormap, invert it, and set the value range to