linestyles in contour?

From what I can gather, I can change the line colors and

    > widths in the contour routine but cannot specify a line
    > style such as dashed, dotted etc.

    > Is this true? If so I would like to have this capability -
    > it makes black and white plots easier to interpret.

There was a bug in the drawing routing for agg line collections that
was preventing us from using this. I fixed it this morning. The new
default is to use dashed lines for contour levels <0.

The contour routine returns (levels, collections) where collections is
a list of LineCollection instances, one for each level. You can now
use the collection.set_linestyle method, which *should* work across
backends. Valid args are

'solid' | 'dashed', 'dashdot', 'dotted' | (offset, on-off-dash-seq)

where the last option allows you to control the dash sequence
explicitly; on-off-dash-seq is an even length sequence of on/off ink
in points. Eg, you can do

  dashes = 0, (5,1,10,3)

which is 5 points on, 1 off, followed by 10 points on, 3 off and then

    > In any case the contour in 0.72 works great - thanks

Glad to hear it -- we'll be adding more features (eg auto-labeling,
poly filling) as we get time.

The linestyle support is in 0.72.1, which I uploaded to the sf site
this morning.