Default 'bin-linear' scale for binned size and opacity channels.
Default 'bin-ordinal' scale for discretized legend
Quantile scale. Legend categories should be <43, 43-53, 53-81 and
>=81.
Quantize scale. Legend categories should be <37, 37-55, 55-73 and
>=73.
Threshold scale. Legend categories should be <30, 30-70 and >=70.
Size Scaling
Default size scaling
Size scaled by with exponent of 2 (by square of radius)
Size scaled with flannery perceptual scaling (exponent of 1.2).
Log to base e scale
Midpoint Scaling
Diverging colour scale with asymmetric extent
Diverging colour scale with asymmetric extent and midpoint set to zero
Domain Scaling
Default data-driven domain
Domain set outside of data bounds
Just min values of domain set outside data bounds.
Just max values of domain set outside data bounds.
Range Scaling
Default range scaling for size and colour.
Size range extended and colour range set with raNums and
raStrs.
Min size range set.
Max size range set.
Colour range set from data field (should be series of greys).
Interactive Scale Parameters
Scale values determined by interactive parameters.