如何使用matplotlib将数组正确绘制为表面？

Question

I'been trying to plot a 3D-image with an array as input. For testing I made an little np.array

ar = np.array([[1,2,3],[4,5,6],[7,8,9]])

My idea was to use the x-positions as x-value, the y-positions as y-value and the value of each position as z-value.

fig = plt.figure(figsize=(12,10))
ax = fig.add_subplot(111, projection='3d')

plt.title("Titel")
X = range(len(a))
Y = range(len(a))
Z = a
ax.plot_surface(X,Y,Z, cmap=plt.cm.Reds, cstride=1, rstride=1)

My problem is that I get an plot, but the plot isnt like I tought it gonna be...

I want a "normal" surface plot, like this:

In the Docs is explained how to make 3D plot with functions as input, but I didnt find a good description how to do it with an array.

Sry for the big pictures, I dont know how to make them smaller :/

Answer 1

Found the solution in this question: Plotting a 2D Array with Matplotlib

Dont know why I didnt see it before.

Adding

x = range(len(a))
y = range(len(a))
X,Y = np.meshgrid(x,y)
Z = a

gives this plot:

I dont know what exactly does "meshgrid"... gonna search a little bit more about it.