Re: [matplotlib-devel] Empty scatter plot

[Eric F. <ef...@ha...>]

On 02/15/2011 07:40 AM, Benjamin Root wrote:
> I have come across a little inconsistency that was unexpected in the
> matplotlib API.  The following is perfectly valid:
>
> import matplotlib.pyplot as plt
> plt.plot([], [])
> plt.show()
>
>
> However, this is not valid:
>
> import matplotlib.pyplot as plt
> plt.scatter([], [])
> plt.show()
>
>
> The immediate issue that comes up in scatter is that it attempts to find
> min/max of the input data for the purpose of autoscaling (this can
> probably be done better by just using set_xmargin(0.05) and
> set_ymargin(0.05)).  This can easily be bypassed with an if statement.
> However, then we discover that polygon collection do not like having
> empty offsets, which leads to a failure in the affine transformation.
>
> So, the question is, is this a bug or a feature?  I personally believe
> that empty data is a perfectly valid scenario and given that other
> matplotlib functions handle it gracefully, we should make the
> collections object more friendly to empty data.

I agree; a call with empty data should simply not plot anything.

Eric

>
> Ben Root
>