Support plots in continuous colourscales (w/o discrete ncols) #88
Description
At the moment, even for inherently continuous colour scales such as 'viridis' and 'plasma', there is no way to request and view/save a plot with the full continuous scale of colours, only the plot produced with some set of N colours pulled from the ncols. This is a major deficiency in my view, since discretising the colour scales can obscure important trends via gradient representation of the visualised data.
To illustrate the difference, compare the colourbar in this (continuous) example and this (discretised) example in the matplotlib gallery.
We should support the continuous case. I will investigate the present logic to see how best to implement this.