Re: [Matplotlib-users] 2D array plot picking explicit values to colour and legend

On 04/09/2012 02:22 AM, Mathew Topper wrote:
> Dear matplotlib-users,
>
> I have a spatial data set that has coded values for each cell, which are
> limited to just a few numbers, ie -8888, 0, 100, and 9999. I would like
> to display this data with a plot similar to pcolor, but I don't want a
> colorbar, I want a legend showing the colors for each code and an
> explanation for what each code represents. I would like to be able to
> choose a subset of the codes as well, for example just plotting the 0
> and 100 codes and ignoring the -8888 and 9999 codes.
>
> I have seen a few similar attempts that used BoundaryNorm, but I don't
> want to show a range of values I just want to set colors for a few
> explicit values. Those examples also had a colorbar and, as I said, I
> would prefer a legend.
>
> Can anyone offer any tips?

For the plot itself you can use pcolor if your data are on a 
quadrilateral grid, or a PathCollection or PolyCollection otherwise. 
For the legend, you can use proxy artists:

http://matplotlib.sourceforge.net/users/legend_guide.html#using-proxy-artist

Eric

>
> Thanks
>
> Mat
>