在 matplotlib 箭袋图中使箭头的大小相同答案

【问题标题】：Make size of arrows all the same in matplotlib quiver plot在 matplotlib 箭袋图中使箭头的大小相同
【发布时间】：2021-07-15 18:06:19
【问题描述】：

我想让 2D quiver plot 中的箭头大小完全相同。在数据文件中，它们的大小不同：

U = np.loadtxt("/home/brendan/software/tf2-model-g/arrays/quiver_array33/u.txt")
V = np.loadtxt("/home/brendan/software/tf2-model-g/arrays/quiver_array33/v.txt")

这里的主要代码：

nx, ny = 240, 426

x1 = range(nx)
y1 = range(ny)

#data
U = np.loadtxt("/home/brendan/software/tf2-model-g/arrays/quiver_array33/u.txt")
V = np.loadtxt("/home/brendan/software/tf2-model-g/arrays/quiver_array33/v.txt")
            
X1, Y1 = np.meshgrid(x1, y1)  # `plot_surface` expects `x` and `y` data to be 2D
            
fig, hf = plt.subplots(figsize=(10,10))
hf.set_title("Model G fluid velocity vector field - every 5th arrow, time = " + str(c1))
Q = hf.quiver(X1[::5, ::5], Y1[::5, ::5], U[::5, ::5], V[::5, ::5], units='width',
      pivot='mid', scale=0.1, headwidth=7)#pivot='mid', units='inches')
qk = hf.quiverkey(Q, 0.9, 0.9, 0.1, r'$\frac{distance}{time}$', labelpos='E',
      coordinates='figure')
hf.scatter(X1[::5, ::5], Y1[::5, ::5], color='r', s=5)

plt.savefig('/home/brendan/software/tf2-model-g/plots/2D_video40/2D_video_velocity_' + str(c1) + '.png')

输出视频图的屏幕截图如下所示：

@Quiver matplotlib : arrow with the same sizesDerek Eden，使用以下代码使随机u 和v 的箭头大小相同。我怎样才能使它适应非随机存储的数据？

x = np.arange(10)
y = np.arange(10)
xx, yy = np.meshgrid(x,y)
u = np.random.uniform(low=-1, high=1, size=(9,9))
v = np.random.uniform(low=-1, high=1, size=(9,9))
plt.quiver(xx, yy, u, v)

【问题讨论】：

标签： python-3.x matplotlib

【解决方案1】：

我通过使用U1、V1 和标准化因子F 标准化数据解决了这个问题：

U = np.loadtxt("/home/brendan/software/tf2-model-g/arrays/quiver_array33/u.txt")
V = np.loadtxt("/home/brendan/software/tf2-model-g/arrays/quiver_array33/v.txt")

N = np.sqrt( U**2 + V**2 )  # normalize data
U1, V1 = U/N, V/N

#F = 0.001 # normalisation factor
F = 0.004

U1 *= F
V1 *= F

X1, Y1 = np.meshgrid(x1, y1)  # `plot_surface` expects `x` and `y` data to be 2D

fig, hf = plt.subplots(figsize=(10,10))
hf.set_title("Model G fluid velocity vector field - every 5th arrow, time = " + str(c1))
Q = hf.quiver(X1[::5, ::5], Y1[::5, ::5], U1[::5, ::5], V1[::5, ::5], units='width',
     pivot='mid', scale=0.1, headwidth=5)
qk = hf.quiverkey(Q, 0.9, 0.9, 0.1, r'$\frac{distance}{time}$', labelpos='E',
     coordinates='figure')
hf.scatter(X1[::5, ::5], Y1[::5, ::5], color='c', s=0)

具有相同大小矢量箭头的绘图结果图像：

【讨论】：