I have NumPy arrays which hold circle centers.
import matplotlib.pylab as plt
import numpy as np
npX = np.asarray(X)
npY = np.asarray(Y)
plt.imshow(img)
// TO-DO
plt.show()
How can I show circles at the given positions on my image?
You can do this with the matplotlib.patches.Circle
patch.
For your example, we need to loop through the X and Y arrays, and then create a circle patch for each coordinate.
Here's an example placing circles on top of an image (from the matplotlib.cbook
)
import matplotlib.pyplot as plt
import numpy as np
from matplotlib.patches import Circle
# Get an example image
import matplotlib.cbook as cbook
image_file = cbook.get_sample_data('grace_hopper.png')
img = plt.imread(image_file)
# Make some example data
x = np.random.rand(5)*img.shape[1]
y = np.random.rand(5)*img.shape[0]
# Create a figure. Equal aspect so circles look circular
fig,ax = plt.subplots(1)
ax.set_aspect('equal')
# Show the image
ax.imshow(img)
# Now, loop through coord arrays, and create a circle at each x,y pair
for xx,yy in zip(x,y):
circ = Circle((xx,yy),50)
ax.add_patch(circ)
# Show the image
plt.show()