Re: [Matplotlib-users] problem with design of matplotlib.pyplot.scatter?

Dr. Phillip M. Feldman wrote:
> I'd like to generate a scatter plot in which symbols are colored using a
> specified colormap, with a specified mapping from the range of the data to
> the [0,1] colormap interval. I thought at first that one could use the norm
> argument to specify a function that would perform this mapping, but from
> closer reading of the documentation (and experimentation) it seems as though
> one cannot do this. Is there another mechanism for doing this? (I could
> remap the data itself before plotting it, but this is unacceptable because
> the colorbar tic lables would then take values in [0,1] rather than values
> from the range of the data).
> 

I don't understand--what you say you want to do is exactly what the norm 
is designed for.  Maybe the problem is that you can't pass in a simple 
function--you need to subclass colors.Normalize.  An example is 
colors.LogNorm.

It looks like what we need is a FuncNorm, which would be initialized 
with two functions, the forward and inverse transformation functions, 
each taking vmin, vmax, and a val.

Eric