How could I plot 3D grid using mplot3d and numpy array?

Question

I am trying to plot a 3D NumPy Array which has integer values.

import numpy as np

def build(self):
    grid = np.empty((10,10,10))
    grid = grid.astype(np.int)
    grid.fill(-1)
    return grid

The previous method builds a 3D grid and fills with -1 value. In this case, -1 is to representation of empty cell.

Putting 3 elements in this grid, for example, in the positions (0,0,0), (0,0,1) y (5,5,5) I do not see same number of elements after plot. I attach an image here.

There is a fourth element on the right of the image (with minor tonality).

My code to plot the grid is as given below:

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

def plot_grid(self, np_grid):
        fig = plt.figure()
        ax = fig.add_subplot(111, projection='3d')
        x = np_grid.sum(0)
        y = np_grid.sum(1)
        z = np_grid.sum(2)
        ax.scatter(x, y, -z, zdir='z', c='red')
        plt.show()

I think I am not getting x,y,z vectors correctly. How could I get x,y,z from ndarray correctly?

The approach here is not understandable. Please provide a minimal reproducible example (including what "(0,0,0), (0,0,1) y (5,5,5)" should do), then clearly explain what should happen. Mind that already grid.fill(-1) will simply put -1 in the array everywhere and summing over the first axis will hence give you 10*(-1) everywhere. — ImportanceOfBeingErnest
– ImportanceOfBeingErnest, Commented Oct 22, 2017 at 14:10

erasmortg · Accepted Answer · 2017-10-22 14:07:54Z

1

I believe your problem is that you need to pass the x, y, and z as arrays of their own:

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')
ax.scatter((0,0,5),(0,0,5),(0,1,5),zdir='z', c='red')

This should give you a plot like this:

answered Oct 22, 2017 at 14:07

erasmortg

3,2881 gold badge20 silver badges34 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

erasmortg Over a year ago

Unless I misunderstood the question, if so, please clarify

Sergio Rodríguez Calvo Over a year ago

Thanks for your reply. You understood well my question. My mistake was I did not know how to build x, y and z vectors. With your answer, you have illustrated how I can do it. I have to take the coordinates of the element that I want to print by separate vectors.

Collectives™ on Stack Overflow

How could I plot 3D grid using mplot3d and numpy array?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related