Matplotlib:以图像为注释的3D散点图
Matplotlib:以图像为注释的3D散点图
提问于 2018-01-10 12:30:39
我正在尝试为包含从0到9的数字的数据集中的图像的tSNE嵌入生成3D散点图。我还想用数据集中的图像注解这些点。
在阅读了与这个问题相关的现有资源后，我发现对于前面提到的here，使用matplotlib.offsetbox可以很容易地完成2D散点图。
还有一个question与3D注释相关，但仅与文本相关。有没有人知道如何用图像而不是文本来标注？
谢谢！
回答 2
Stack Overflow用户
回答已采纳
发布于 2018-01-16 21:02:25
matplotlib.offsetbox在3D模式下不起作用。作为一种变通方法，可以使用覆盖3D绘图的2D轴，并将对该2D轴的图像注释放置在与3D轴中的位置相对应的位置。
要计算这些位置的坐标，可以参考How to transform 3d data units to display units with matplotlib?。然后，可以使用这些显示坐标的逆变换来获得覆盖轴上的新坐标。
from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d import proj3d
import matplotlib.pyplot as plt
from matplotlib import offsetbox
import numpy as np
xs = [1,1.5,2,2]
ys = [1,2,3,1]
zs = [0,1,2,0]
c = ["b","r","g","gold"]
fig = plt.figure()
ax = fig.add_subplot(111, projection=Axes3D.name)
ax.scatter(xs, ys, zs, c=c, marker="o")
# Create a dummy axes to place annotations to
ax2 = fig.add_subplot(111,frame_on=False)
ax2.axis("off")
ax2.axis([0,1,0,1])
def proj(X, ax1, ax2):
""" From a 3D point in axes ax1,
calculate position in 2D in ax2 """
x,y,z = X
x2, y2, _ = proj3d.proj_transform(x,y,z, ax1.get_proj())
return ax2.transData.inverted().transform(ax1.transData.transform((x2, y2)))
def image(ax,arr,xy):
""" Place an image (arr) as annotation at position xy """
im = offsetbox.OffsetImage(arr, zoom=2)
im.image.axes = ax
ab = offsetbox.AnnotationBbox(im, xy, xybox=(-30., 30.),
xycoords='data', boxcoords="offset points",
pad=0.3, arrowprops=dict(arrowstyle="->"))
ax.add_artist(ab)
for s in zip(xs,ys,zs):
x,y = proj(s, ax, ax2)
image(ax2,np.random.rand(10,10),[x,y])
ax.set_xlabel('X Label')
ax.set_ylabel('Y Label')
ax.set_zlabel('Z Label')
plt.show()
上面的解决方案是静态的。这意味着如果旋转或缩放绘图，注释将不再指向正确的位置。为了同步注解，用户可以连接到绘制事件，检查界限或视角是否已更改，并相应地更新注解坐标。(2019年编辑:更新的版本还需要将事件从顶部2D轴传递到底部3D轴；代码更新)
from mpl_toolkits.mplot3d import Axes3D
from mpl_toolkits.mplot3d import proj3d
import matplotlib.pyplot as plt
from matplotlib import offsetbox
import numpy as np
xs = [1,1.5,2,2]
ys = [1,2,3,1]
zs = [0,1,2,0]
c = ["b","r","g","gold"]
fig = plt.figure()
ax = fig.add_subplot(111, projection=Axes3D.name)
ax.scatter(xs, ys, zs, c=c, marker="o")
# Create a dummy axes to place annotations to
ax2 = fig.add_subplot(111,frame_on=False)
ax2.axis("off")
ax2.axis([0,1,0,1])
class ImageAnnotations3D():
def __init__(self, xyz, imgs, ax3d,ax2d):
self.xyz = xyz
self.imgs = imgs
self.ax3d = ax3d
self.ax2d = ax2d
self.annot = []
for s,im in zip(self.xyz, self.imgs):
x,y = self.proj(s)
self.annot.append(self.image(im,[x,y]))
self.lim = self.ax3d.get_w_lims()
self.rot = self.ax3d.get_proj()
self.cid = self.ax3d.figure.canvas.mpl_connect("draw_event",self.update)
self.funcmap = {"button_press_event" : self.ax3d._button_press,
"motion_notify_event" : self.ax3d._on_move,
"button_release_event" : self.ax3d._button_release}
self.cfs = [self.ax3d.figure.canvas.mpl_connect(kind, self.cb) \
for kind in self.funcmap.keys()]
def cb(self, event):
event.inaxes = self.ax3d
self.funcmap[event.name](event)
def proj(self, X):
""" From a 3D point in axes ax1,
calculate position in 2D in ax2 """
x,y,z = X
x2, y2, _ = proj3d.proj_transform(x,y,z, self.ax3d.get_proj())
tr = self.ax3d.transData.transform((x2, y2))
return self.ax2d.transData.inverted().transform(tr)
def image(self,arr,xy):
""" Place an image (arr) as annotation at position xy """
im = offsetbox.OffsetImage(arr, zoom=2)
im.image.axes = ax
ab = offsetbox.AnnotationBbox(im, xy, xybox=(-30., 30.),
xycoords='data', boxcoords="offset points",
pad=0.3, arrowprops=dict(arrowstyle="->"))
self.ax2d.add_artist(ab)
return ab
def update(self,event):
if np.any(self.ax3d.get_w_lims() != self.lim) or \
np.any(self.ax3d.get_proj() != self.rot):
self.lim = self.ax3d.get_w_lims()
self.rot = self.ax3d.get_proj()
for s,ab in zip(self.xyz, self.annot):
ab.xy = self.proj(s)
imgs = [np.random.rand(10,10) for i in range(len(xs))]
ia = ImageAnnotations3D(np.c_[xs,ys,zs],imgs,ax, ax2 )
ax.set_xlabel('X Label')
ax.set_ylabel('Y Label')
ax.set_zlabel('Z Label')
plt.show()
Stack Overflow用户
发布于 2021-07-23 09:33:58
您可以使用Tensorboard embedding projector作为matplotlib的替代。带代码的Example。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/48180327
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