Do not show null values ​​on a 2D heat map

Question

I want to build a two-dimensional map of a syllicon plate. Therefore, only the central part has a value, and the corners have a value of 0. I use matplotlib plt.imshow to get a simple map as follows:

data = np.array([[ 0. ,  0. ,  1. ,  1. ,  0. ,  0. ],
       [ 0. ,  1. ,  1. ,  1. ,  1. ,  0. ],
       [ 1. ,  2. ,  0.1,  2. ,  2. ,  1. ],
       [ 1. ,  2. ,  2. ,  0.1,  2. ,  1. ],
       [ 0. ,  1. ,  1. ,  1. ,  1. ,  0. ],
       [ 0. ,  0. ,  1. ,  1. ,  0. ,  0. ]])

plt.figure(1)
plt.imshow(data ,interpolation='none')
plt.colorbar()

And I get the following card:

Is there a way to remove the dark blue areas where the values ​​are zeros while maintaining the shape of the “plate” (green, red, and light blue areas)? The value of the corners would be white, while the rest would preserve the color configuration.

Or is there a better function I could use to get this?

Answer 1

There are two ways to get rid of the blue corners:

:

data[data == 0] = np.nan
plt.imshow(data, interpolation = 'none', vmin = 0)

imshow:

data_masked = np.ma.masked_where(data == 0, data)
plt.imshow(data_masked, interpolation = 'none', vmin = 0)

, , .

, vmin/vmax . vmin = 0 plt.imshow , .