This reads like the "similar cases" are logarithmic scaling, but you are referring to linear colour scaling aren't you? I don't think it reads well. You should be specific about this e.g.:
```
For linear colour scaling it is perfectly practical to select a suitable colormap and allow
contour to pick the level colours automatically from that, provided that the data range is
symmetric about zero, and that the colormap is diverging (see the 'Diverging colormaps'
section in: `<http://matplotlib.org/examples/color/colormaps_reference.html>`_).
```
Something along these lines?