Matplotlib: annoter un nuage de points 3D

Question

J'essaie de générer un nuage de points 3D en utilisant Matplotlib. Je voudrais annoter des points individuels comme le cas 2D ici: Matplotlib: Comment mettre des balises individuelles pour un nuage de points .

J'ai essayé d'utiliser cette fonction et j'ai consulté le document Matplotlib, mais j'ai trouvé que la bibliothèque ne prend pas en charge l'annotation 3D. Est-ce que quelqu'un sait comment faire ça?

Merci!

Answer 1

Calculez la position 2D du point et utilisez-la pour créer l'annotation. Si vous avez besoin d'interaction avec la figure, vous pouvez recalculer l'emplacement lorsque la souris est relâchée.

import pylab
from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d import proj3d
fig = pylab.figure()
ax = fig.add_subplot(111, projection = '3d')
x = y = z = [1, 2, 3]
sc = ax.scatter(x,y,z)
# now try to get the display coordinates of the first point

x2, y2, _ = proj3d.proj_transform(1,1,1, ax.get_proj())

label = pylab.annotate(
    "this", 
    xy = (x2, y2), xytext = (-20, 20),
    textcoords = 'offset points', ha = 'right', va = 'bottom',
    bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
    arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))

def update_position(e):
    x2, y2, _ = proj3d.proj_transform(1,1,1, ax.get_proj())
    label.xy = x2,y2
    label.update_positions(fig.canvas.renderer)
    fig.canvas.draw()
fig.canvas.mpl_connect('button_release_event', update_position)
pylab.show()

Answer 2

Peut-être plus facile via ax.text (...):

from matplotlib import pyplot
from mpl_toolkits.mplot3d import Axes3D
from numpy.random import Rand
from pylab import figure


m=Rand(3,3) # m is an array of (x,y,z) coordinate triplets

fig = figure()
ax = Axes3D(fig)


for i in range(len(m)): #plot each point + it's index as text above
 ax.scatter(m[i,0],m[i,1],m[i,2],color='b') 
 ax.text(m[i,0],m[i,1],m[i,2],  '%s' % (str(i)), size=20, zorder=1,  
 color='k') 

ax.set_xlabel('x')
ax.set_ylabel('y')
ax.set_zlabel('z')
pyplot.show()

Answer 3

Dans les articles suivants [1] , [2] le traçage des flèches 3D dans matplotlib est discuté.

De même, la classe Annotation3D (héritée d'Annotation) peut être créée:

from mpl_toolkits.mplot3d.proj3d import proj_transform
from matplotlib.text import Annotation

class Annotation3D(Annotation):
    '''Annotate the point xyz with text s'''

    def __init__(self, s, xyz, *args, **kwargs):
        Annotation.__init__(self,s, xy=(0,0), *args, **kwargs)
        self._verts3d = xyz        

    def draw(self, renderer):
        xs3d, ys3d, zs3d = self._verts3d
        xs, ys, zs = proj_transform(xs3d, ys3d, zs3d, renderer.M)
        self.xy=(xs,ys)
        Annotation.draw(self, renderer)

De plus, nous pouvons définir la fonction annotate3D ():

def annotate3D(ax, s, *args, **kwargs):
    '''add anotation text s to to Axes3d ax'''

    tag = Annotation3D(s, *args, **kwargs)
    ax.add_artist(tag)

En utilisant cette fonction, les balises d'annotation peuvent être ajoutées à Axes3d comme dans l'exemple ci-dessous:

import matplotlib.pyplot as plt    
from mpl_toolkits.mplot3d import axes3d
from mpl_toolkits.mplot3d.art3d import Line3DCollection

# data: coordinates of nodes and links
xn = [1.1, 1.9, 0.1, 0.3, 1.6, 0.8, 2.3, 1.2, 1.7, 1.0, -0.7, 0.1, 0.1, -0.9, 0.1, -0.1, 2.1, 2.7, 2.6, 2.0]
yn = [-1.2, -2.0, -1.2, -0.7, -0.4, -2.2, -1.0, -1.3, -1.5, -2.1, -0.7, -0.3, 0.7, -0.0, -0.3, 0.7, 0.7, 0.3, 0.8, 1.2]
zn = [-1.6, -1.5, -1.3, -2.0, -2.4, -2.1, -1.8, -2.8, -0.5, -0.8, -0.4, -1.1, -1.8, -1.5, 0.1, -0.6, 0.2, -0.1, -0.8, -0.4]
group = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 2, 2, 2, 3, 3, 3, 3]
edges = [(1, 0), (2, 0), (3, 0), (3, 2), (4, 0), (5, 0), (6, 0), (7, 0), (8, 0), (9, 0), (11, 10), (11, 3), (11, 2), (11, 0), (12, 11), (13, 11), (14, 11), (15, 11), (17, 16), (18, 16), (18, 17), (19, 16), (19, 17), (19, 18)]
xyzn = Zip(xn, yn, zn)
segments = [(xyzn[s], xyzn[t]) for s, t in edges]                

# create figure        
fig = plt.figure(dpi=60)
ax = fig.gca(projection='3d')
ax.set_axis_off()

# plot vertices
ax.scatter(xn,yn,zn, marker='o', c = group, s = 64)    
# plot edges
Edge_col = Line3DCollection(segments, lw=0.2)
ax.add_collection3d(Edge_col)
# add vertices annotation.
for j, xyz_ in enumerate(xyzn): 
    annotate3D(ax, s=str(j), xyz=xyz_, fontsize=10, xytext=(-3,3),
               textcoords='offset points', ha='right',va='bottom')    
plt.show()

Answer 4

Si vous avez de nombreux points de données, le graphique peut devenir très encombré si vous les annotez tous. La solution suivante (basée sur la réponse d'HYRY) implémente une solution de survol (pop-over) pour les points de données dans les graphiques 3D. Seul le point de données à côté de la position de votre souris sera annoté. Après chaque mouvement de la souris, la distance du pointeur de la souris à tous les points de données est calculée et le point le plus proche est annoté.

import matplotlib.pyplot as plt, numpy as np
from mpl_toolkits.mplot3d import proj3d

def visualize3DData (X):
    """Visualize data in 3d plot with popover next to mouse position.

    Args:
        X (np.array) - array of points, of shape (numPoints, 3)
    Returns:
        None
    """
    fig = plt.figure(figsize = (16,10))
    ax = fig.add_subplot(111, projection = '3d')
    ax.scatter(X[:, 0], X[:, 1], X[:, 2], depthshade = False, picker = True)


    def distance(point, event):
        """Return distance between mouse position and given data point

        Args:
            point (np.array): np.array of shape (3,), with x,y,z in data coords
            event (MouseEvent): mouse event (which contains mouse position in .x and .xdata)
        Returns:
            distance (np.float64): distance (in screen coords) between mouse pos and data point
        """
        assert point.shape == (3,), "distance: point.shape is wrong: %s, must be (3,)" % point.shape

        # Project 3d data space to 2d data space
        x2, y2, _ = proj3d.proj_transform(point[0], point[1], point[2], plt.gca().get_proj())
        # Convert 2d data space to 2d screen space
        x3, y3 = ax.transData.transform((x2, y2))

        return np.sqrt ((x3 - event.x)**2 + (y3 - event.y)**2)


    def calcClosestDatapoint(X, event):
        """"Calculate which data point is closest to the mouse position.

        Args:
            X (np.array) - array of points, of shape (numPoints, 3)
            event (MouseEvent) - mouse event (containing mouse position)
        Returns:
            smallestIndex (int) - the index (into the array of points X) of the element closest to the mouse position
        """
        distances = [distance (X[i, 0:3], event) for i in range(X.shape[0])]
        return np.argmin(distances)


    def annotatePlot(X, index):
        """Create popover label in 3d chart

        Args:
            X (np.array) - array of points, of shape (numPoints, 3)
            index (int) - index (into points array X) of item which should be printed
        Returns:
            None
        """
        # If we have previously displayed another label, remove it first
        if hasattr(annotatePlot, 'label'):
            annotatePlot.label.remove()
        # Get data point from array of points X, at position index
        x2, y2, _ = proj3d.proj_transform(X[index, 0], X[index, 1], X[index, 2], ax.get_proj())
        annotatePlot.label = plt.annotate( "Value %d" % index,
            xy = (x2, y2), xytext = (-20, 20), textcoords = 'offset points', ha = 'right', va = 'bottom',
            bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
            arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))
        fig.canvas.draw()


    def onMouseMotion(event):
        """Event that is triggered when mouse is moved. Shows text annotation over data point closest to mouse."""
        closestIndex = calcClosestDatapoint(X, event)
        annotatePlot (X, closestIndex)

    fig.canvas.mpl_connect('motion_notify_event', onMouseMotion)  # on mouse motion
    plt.show()


if __== '__main__':
    X = np.random.random((30,3))
    visualize3DData (X)

Answer 5

Dans le cas où vous souhaitez faire tourner la réponse de @ msch:

from mpl_toolkits.mplot3d import axes3d
import matplotlib.pyplot as plt
from numpy.random import Rand

m = Rand(3,3) # m is an array of (x,y,z) coordinate triplets

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

for i in range(len(m)): # plot each point + it's index as text above
  x = m[i,0]
  y = m[i,1]
  z = m[i,2]
  label = i
  ax.scatter(x, y, z, color='b')
  ax.text(x, y, z, '%s' % (label), size=20, zorder=1, color='k')

ax.set_xlabel('x')
ax.set_ylabel('y')
ax.set_zlabel('z')

for angle in range(0, 360):
  ax.view_init(30, angle)
  plt.draw()
  plt.pause(.001)

Answer 6

Voici une forme légèrement plus générale de l'excellente réponse d'HYRY. Cela fonctionne pour n'importe quelle liste de points et d'étiquettes.

import numpy as np
from matplotlib import pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d import proj3d

points = np.array([(1,1,1), (2,2,2)])
labels = ['billy', 'bobby']

fig = plt.figure()
ax = fig.add_subplot(111, projection = '3d')
xs, ys, zs = np.split(points, 3, axis=1)
sc = ax.scatter(xs,ys,zs)

# if this code is placed inside a function, then
# we must use a predefined global variable so that
# the update function has access to it. I'm not
# sure why update_positions() doesn't get access
# to its enclosing scope in this case.
global labels_and_points
labels_and_points = []

for txt, x, y, z in Zip(labels, xs, ys, zs):
    x2, y2, _ = proj3d.proj_transform(x,y,z, ax.get_proj())
    label = plt.annotate(
        txt, xy = (x2, y2), xytext = (-20, 20),
        textcoords = 'offset points', ha = 'right', va = 'bottom',
        bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
        arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))
    labels_and_points.append((label, x, y, z))


def update_position(e):
    for label, x, y, z in labels_and_points:
        x2, y2, _ = proj3d.proj_transform(x, y, z, ax.get_proj())
        label.xy = x2,y2
        label.update_positions(fig.canvas.renderer)
    fig.canvas.draw()

fig.canvas.mpl_connect('motion_notify_event', update_position)

plt.show()

Il y a un problème ennuyeux d'espace de nom que je ne pouvais résoudre qu'en utilisant (de manière piratée) une variable globale. Si quelqu'un peut fournir une meilleure solution ou expliquer ce qui se passe, faites-le moi savoir!

Answer 7

Cette réponse est basée sur la réponse précédente de user315582. J'ai fait quelques modifications pour fournir une solution sans utiliser de variables globales.

import numpy as np
from matplotlib import pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d import proj3d

def main():
    fig = plt.figure()
    ax = fig.add_subplot(111, projection = '3d')
    points = np.array([(1,1,1), (2,2,2)])
    labels = ['billy', 'bobby']
    plotlabels = []
    xs, ys, zs = np.split(points, 3, axis=1)
    sc = ax.scatter(xs,ys,zs)

    for txt, x, y, z in Zip(labels, xs, ys, zs):
        x2, y2, _ = proj3d.proj_transform(x,y,z, ax.get_proj())
        label = plt.annotate(
            txt, xy = (x2, y2), xytext = (-20, 20),
            textcoords = 'offset points', ha = 'right', va = 'bottom',
            bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
            arrowprops = dict(arrowstyle = '-', connectionstyle = 'arc3,rad=0'))
        plotlabels.append(label)
    fig.canvas.mpl_connect('motion_notify_event', lambda event: update_position(event,fig,ax,Zip(plotlabels, xs, ys, zs)))
    plt.show()


def update_position(e,fig,ax,labels_and_points):
    for label, x, y, z in labels_and_points:
        x2, y2, _ = proj3d.proj_transform(x, y, z, ax.get_proj())
        label.xy = x2,y2
        label.update_positions(fig.canvas.renderer)
    fig.canvas.draw()



if __== '__main__':
    main()