In [1]:

    

import skimage.io
import matplotlib.pyplot as plt
import numpy as np
%matplotlib inline


    

    




/Users/baart_f/.virtualenvs/main/lib/python3.5/site-packages/matplotlib/__init__.py:872: UserWarning: axes.color_cycle is deprecated and replaced with axes.prop_cycle; please use the latter.
  warnings.warn(self.msg_depr % (key, alt_key))

In [2]:

    

img = skimage.io.imread('/Users/baart_f/Documents/tellen.png')


    

In [3]:

    

fig, axes = plt.subplots(1, 4, figsize=(18,6))
axes[0].imshow(img)
is_nl = img[:,:,3] > 0
axes[1].imshow(is_nl)
new_land = np.logical_and(img[:,:,1] < 100, is_nl)
new_water = np.logical_and(img[:,:,2] > 105, is_nl)


axes[2].imshow(new_land, cmap='Greys')
new_land.any(), new_land.all()


    

    
Out[3]:





(True, False)






    

In [4]:

    

_ = plt.hist(img[:,:,2].ravel(), bins=100)


    

In [5]:

    

plt.plot(
    img[is_nl,1].ravel(), 
    img[is_nl,2].ravel(), 
    'k.', alpha=0.2
)


    

    
Out[5]:





[<matplotlib.lines.Line2D at 0x11b45dfd0>]






    

In [6]:

    

# bottom right
new_land = np.logical_and.reduce([
        img[:,:,2] < 120, 
        img[:,:,1] > 120, 
        is_nl
])
plt.imshow(new_land, cmap='Greys')


    

    
Out[6]:





<matplotlib.image.AxesImage at 0x11dbabb38>






    

In [7]:

    

# top
new_water = np.logical_and.reduce([
        img[:,:,2] >= 120, 
        img[:,:,1] > 100, 
        is_nl
])
plt.imshow(new_water, cmap='Greys')


    

    
Out[7]:





<matplotlib.image.AxesImage at 0x11e2fe8d0>






    

In [8]:

    

print(new_land.sum()/is_nl.sum(), new_water.sum()/is_nl.sum())


    

    




0.00646476314136 0.00627400309432

In [10]:

    

plt.imshow(new_land, cmap='Greens', alpha=0.5)
plt.imshow(new_water, cmap='Blues', alpha=0.5)


    

    
Out[10]:





<matplotlib.image.AxesImage at 0x11e30f940>






    

In [ ]: