pyosv.plot.plot

  1import matplotlib.pyplot as plt
  2import numpy as np
  3
  4def plot(img : np.ndarray, hist : bool = False) -> None:
  5    '''
  6        Plot a satellite image and its histogram.
  7
  8        Only gray-scale or RGB-like are accepted.
  9
 10        Parameters:
 11        ----------
 12            - img : np.ndarray
 13                a WxHxB image, with width W, height H and B bands (B can be 3 or 1)
 14            - hist : bool
 15                if True display also the histogram (dafault : False)
 16        
 17        Returns:
 18        --------
 19        Nothing, it will display the image
 20
 21        Usage:
 22        ------
 23
 24        ```python
 25        import numpy as np
 26
 27        img         = np.array(  
 28            [[
 29                [0.1, 0.2, 0.3],  
 30                [0.4, 0.5, 0.6],  
 31                [0.7, 0.8, 0.9]
 32             ]
 33            ]  
 34        ) 
 35
 36        # Adding fake axis
 37        img = img[:,:,None]
 38
 39        plot(img, hist=True)
 40
 41        ```
 42
 43        Output:
 44        -------
 45        Nothing, it will display the image
 46    '''
 47    
 48
 49    if len(img.shape) != 3:
 50        raise Exception('Error: lenght of image shape must be 3 - (space, space, channels)')
 51
 52    if ((img.shape[-1] != 1) and (img.shape[-1] != 3)):
 53        raise Exception("Error: numer of channels admitted are 1 or 3")
 54
 55
 56    ncols = 1
 57    if hist: ncols = 2
 58    
 59    fig, axes = plt.subplots(nrows = 1, ncols = ncols, figsize = (4*ncols, 4))
 60
 61    if hist:
 62        axes[0].imshow(img)
 63        axes[0].set_title('Image')
 64        for b in range(img.shape[-1]):
 65            axes[1].hist(img[:,:,b].flatten(), 200, label='Band {}'.format(b))
 66        axes[1].legend()
 67        axes[1].set_title('Histogram')
 68    else:
 69        axes.imshow(img)
 70        axes.set_title('Image')
 71        
 72    fig.tight_layout()
 73    plt.show()
 74
 75
 76def bands_plot(img : np.ndarray, hist : bool = False) -> None:
 77    '''
 78        Plot a satellite image bands and relative histograms.
 79
 80        Parameters:
 81        ----------
 82            - img : np.ndarray
 83                a WxHxB image, with width W, height H and B bands
 84            - hist : bool
 85                if True display also the histograms (dafault : False)
 86        
 87        Returns:
 88        --------
 89        Nothing, it will display the image
 90
 91        Usage:
 92        ------
 93
 94        ```python
 95        import numpy as np
 96
 97        img         = np.array(  
 98            [[
 99                [0.1, 0.2, 0.3],  
100                [0.4, 0.5, 0.6],  
101                [0.7, 0.8, 0.9]
102             ],
103             [
104                [1.1, 1.2, 1.3],  
105                [1.4, 1.5, 1.6],  
106                [1.7, 1.8, 1.9]
107             ]
108            ]  
109        ) 
110
111        # Adding fake axis
112        img = np.moveaxis(img, 0, -1)
113
114        bands_plot(img, hist=True)
115
116        ```
117
118        Output:
119        -------
120        Nothing, it will display the image
121    '''
122    
123    if len(img.shape) != 3:
124        raise Exception('Error: lenght of image shape must be 3 - (space, space, channels)')
125    
126    ncols = img.shape[-1]
127    nrows = 1
128    if hist: nrows = 2
129    
130    fig, axes = plt.subplots(nrows = nrows, ncols = ncols, figsize = (4*ncols, 4*nrows))
131
132    for c in range(ncols):
133        
134        if hist:
135            axes[0,c].imshow(img[:,:,c])
136            axes[0,c].set_title('Bands {}'.format(c))
137                
138            axes[1,c].hist(img[:,:,c].flatten(), 200)
139            axes[1,c].set_title('Histogram of Band {}'.format(c))
140        else:
141            axes[c].imshow(img[:,:,c])
142            axes[c].set_title('Band {}'.format(c))
143
144    fig.tight_layout()
145    plt.show()