bar3d 图中的错误重叠 [英] Wrong overlap in bar3d plot

问题描述

我已经制作了这个 3d 条形图，但我发现一些条形中有错误的重叠，如下图的绿色圆圈所示:

I've made this 3d bar plot, but I've found a wrong overlap in some bars, as I show in the image below with green circles:

情节是由:

import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.mplot3d.axes3d import Axes3D
import matplotlib.colors as colors

fig = plt.figure(figsize=(10,8))
ax = fig.add_subplot(111, projection='3d')    
matrix = np.array([
[84 80 68 56 60 44 55 39 27 29]
[82 67 63 44 47 33 22 19  9  2]
[53 61 48 34  0 16  0  0  0  0]
[48 25  0  0  0  0  0  0  0  0]])

len_x, len_y = matrix.shape
_x = np.arange(len_x)
_y = np.arange(len_y)

xpos, ypos = np.meshgrid(_x, _y)
xpos = xpos.flatten('F')
ypos = ypos.flatten('F')
zpos = np.zeros_like(xpos)

dx = np.ones_like(zpos)
dy = dx.copy()
dz = matrix.flatten()

cmap=plt.cm.magma(plt.Normalize(0,100)(dz))

ax.bar3d(xpos+0.32, ypos-0.3, zpos, dx-0.6, dy-0.1, dz, zsort='max', color=cmap)

ax.set_xlabel('x')
ax.set_xticks(np.arange(len_x+1))
ax.set_xticklabels(['1000','500','100','50','0'])
ax.set_xlim(0,4)
ax.set_ylabel('y')
ax.set_yticks(np.arange(len_y+1))
ax.set_yticklabels(['0.5','1.','1.5','2.','2.5','3.','3.5','4.','4.5','5.'])
ax.set_ylim(-0.5,10)
ax.set_zlabel('z')
ax.set_zlim(0,100)
ax.view_init(ax.elev, ax.azim+100)

这是一个错误吗?为什么有些条形严重重叠?我使用的是 matplotlib 2.1.0 版和 anaconda python 3.6.3

Is it a bug? Why some bars are badly overlapping? I'm using matplotlib version 2.1.0 and anaconda python 3.6.3

推荐答案

正如@DavidG 在评论中指出的，这是一个没有理想解决方案的问题:

As pointed out by @DavidG in the comments, this is an issue without an ideal solution:

我的 3D 绘图在某些视角下看起来不正确
这可能是 mplot3d 最常报告的问题.问题是从某些视角来看，一个 3D 对象会出现在另一个物体，即使它在物理上位于它的后面.这个可以导致绘图看起来物理上不正确".

My 3D plot doesn’t look right at certain viewing angles
This is probably the most commonly reported issue with mplot3d. The problem is that – from some viewing angles – a 3D object would appear in front of another object, even though it is physically behind it. This can result in plots that do not look "physically correct."

不幸的是，虽然正在进行一些工作以减少发生这个神器，目前是一个棘手的问题，不能完全解决，直到 matplotlib 支持 3D 图形渲染核心.
[来源]

Unfortunately, while some work is being done to reduce the occurrence of this artifact, it is currently an intractable problem, and can not be fully solved until matplotlib supports 3D graphics rendering at its core.
[Source]

但是，通过调整绘图的视角并减少条形之间的接触面积，我能够大大减少这个问题.

However, I was able to greatly reduce this issue by playing with the viewing angle of the plots and reducing the contact areas between the bars.

例如，要更改视角(相机位置")，我使用了:

For example, to change the viewing angle (the "camera position"), I used:

ax.view_init(elev=30, azim=-60) # Changes the elevation and azimuth

如何使用 python/matplotlib 为 3d 绘图设置相机位置"中的更多详细信息?

根据接触区域，这取决于您的情节.在我的例子中，所有的条形都与 y 轴接触，所以我只是减少了 dy 参数以在条形之间留下一些间隙.

As per the contact areas, it depends on your plot. In my case, all the bars had contact alongside the y axis, so I just reduced the dy param a little to left some gap between the bars.

这篇关于bar3d 图中的错误重叠的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！