00 載入擴展庫

import numpy as np
import matplotlib.pyplot as plt

01 顯示圖片
img=plt.imread('D:\Anoconda\lena.jpg')
plt.figure(figsize=(10,5))
plt.subplot(121)
plt.imshow(img)
plt.subplot(122)
plt.imshow(img,origin='lower')

02 繪制等值線圖

import numpy as np
import matplotlib.pyplot as plt
x=np.linspace(-2,2,200).reshape(1,-1)
y=np.linspace(-2,2,200).reshape(-1,1)
ext=[np.min(x),np.max(x),np.min(y),np.max(y)]
z=x*np.exp(-x**2-y**2)
plt.imshow(z,extent=ext)

import numpy as np
import matplotlib.pyplot as plt
x=np.linspace(-2,2,200).reshape(1,-1)
y=np.linspace(-2,2,200).reshape(-1,1)
ext=[np.min(x),np.max(x),np.min(y),np.max(y)]
z=x*np.exp(-x**2-y**2)
cs=plt.contour(z,8,extent=ext)
plt.clabel(cs)

import numpy as np
import matplotlib.pyplot as plt
x=np.linspace(-2,2,200).reshape(1,-1)
y=np.linspace(-2,2,200).reshape(-1,1)
z=x*np.exp(-x**2-y**2)
plt.contourf(x.ravel(),y.ravel(),z,10)
plt.colorbar()