Question

问题： 绘制闭合的2D多边形可以正常工作。当我尝试将其绘制为1D（通过用常量替换第二个维度）时，它会在某些特殊情况中失败：然后多边形（变成一条线）不会完全绘制。

我尝试了什么：

不同的绘图风格，如. , o --，其中只有后者才能重现问题，而非线状风格则有效。
移动/滚动多边形阵列，当移动1或2时不起作用，但是3和4解决了这个问题。
问一个无能为力的朋友^^
通过直接在x.min()和x.max()之间划一条线来帮助自己。
为简单起见，我删除了z-Data。当将x与z组合绘制时，它也可以工作 - 只要z远离常数即可。但后来我得到一个摇摆不定的图形而不是一条直线。

仍然怎么可能，数据是否完全绘制取决于它的顺序？我做错了什么？

我尝试减少其中一个特殊情况的数据，但没有走得太远。这是生成图像的工作迷你示例，对于长数据集我很抱歉，但在保持问题可重现性的同时无法找出要删除的值。

import numpy as np
from matplotlib import pyplot as plt

s = np.array([
       [-0.08527125,  0.08810856],
       [-0.08967261, -0.06748633],
       [-0.08772675, -0.08396971],
       [-0.08766724, -0.08440267],
       [-0.08748191, -0.08521958],
       [-0.08438602, -0.09529874],
       [-0.08385044, -0.09684308],
       [-0.08202714, -0.10180355],
       [-0.07874478, -0.1066276 ],
       [-0.07857811, -0.10686354],
       [-0.07789635, -0.10778213],
       [-0.07781094, -0.10789337],
       [-0.07710836, -0.10880646],
       [-0.07007289, -0.11655674],
       [-0.06962708, -0.11703841],
       [-0.06727917, -0.11933749],
       [-0.06584873, -0.12070607],
       [-0.06552574, -0.12100522],
       [-0.06527846, -0.12121293],
       [-0.06401669, -0.12214381],
       [-0.06349801, -0.12245992],
       [-0.06328962, -0.12258028],
       [-0.0627093 , -0.12290901],
       [-0.06225359, -0.12314782],
       [-0.06116991, -0.12368258],
       [-0.06041895, -0.12403051],
       [-0.06017477, -0.12413955],
       [-0.05992829, -0.12424804],
       [-0.04659197, -0.13006904],
       [-0.04634663, -0.13017319],
       [-0.04628731, -0.1301966 ],
       [-0.04567821, -0.13041967],
       [-0.04552972, -0.13047215],
       [-0.04521702, -0.13058213],
       [-0.00325617, -0.14513102],
       [ 0.00180445, -0.14683444],
       [ 0.00950078, -0.14923653],
       [ 0.01392647, -0.15030046],
       [ 0.01518804, -0.15045976],
       [ 0.02734024, -0.15177574],
       [ 0.02813995, -0.15177997],
       [ 0.02882764, -0.15176844],
       [ 0.02947446, -0.15171012],
       [ 0.03001744, -0.15165147],
       [ 0.0309922 , -0.15149313],
       [ 0.03121784, -0.15145567],
       [ 0.031327  , -0.15143527],
       [ 0.03142507, -0.15141573],
       [ 0.03150791, -0.15139799],
       [ 0.03222764, -0.15124224],
       [ 0.03798838, -0.14988557],
       [ 0.038991  , -0.1496481 ],
       [ 0.0391266 , -0.14961472],
       [ 0.03920601, -0.14959498],
       [ 0.03938681, -0.14954736],
       [ 0.03991586, -0.14940614],
       [ 0.05465674, -0.14538513],
       [ 0.05500815, -0.14528457],
       [ 0.05512499, -0.14524203],
       [ 0.05522656, -0.14520209],
       [ 0.05558739, -0.14504381],
       [ 0.05580602, -0.1449474 ],
       [ 0.05609256, -0.14478439],
       [ 0.05713959, -0.14412759],
       [ 0.05743526, -0.14392656],
       [ 0.05889567, -0.14277855],
       [ 0.06059875, -0.14143159],
       [ 0.06530732, -0.13766523],
       [ 0.06933674, -0.13424303],
       [ 0.0702827 , -0.13335664],
       [ 0.07036637, -0.13327235],
       [ 0.07405533, -0.12951652],
       [ 0.07810863, -0.125367  ],
       [ 0.08087981, -0.12226141],
       [ 0.08176499, -0.12123622],
       [ 0.08381519, -0.1150717 ],
       [ 0.08734418, -0.0927558 ],
       [ 0.08230393,  0.09131774],
       [ 0.08183173,  0.097691  ],
       [ 0.08169106,  0.09931977],
       [ 0.08130204,  0.10177584],
       [ 0.07914312,  0.11230088],
       [ 0.07895476,  0.11316267],
       [ 0.07514703,  0.12076318],
       [ 0.07464758,  0.12166996],
       [ 0.0733333 ,  0.12382546],
       [ 0.07297538,  0.12425848],
       [ 0.06620658,  0.13199037],
       [ 0.05294461,  0.14660768],
       [ 0.05262742,  0.14694802],
       [ 0.05097036,  0.14849098],
       [ 0.04972845,  0.14937964],
       [ 0.04815287,  0.15002114],
       [ 0.04783434,  0.15013311],
       [ 0.04757239,  0.15022502],
       [ 0.02928349,  0.15634586],
       [ 0.02842644,  0.15662035],
       [ 0.02776939,  0.15677726],
       [ 0.0270936 ,  0.15690821],
       [ 0.02666639,  0.15698384],
       [ 0.02610376,  0.15707915],
       [ 0.02601474,  0.15709266],
       [ 0.025126  ,  0.15722434],
       [ 0.02474755,  0.15727606],
       [ 0.02296123,  0.15742128],
       [ 0.02202472,  0.15744494],
       [ 0.02086636,  0.15744469],
       [ 0.01967163,  0.15742308],
       [ 0.01872141,  0.15737815],
       [ 0.01568162,  0.15718458],
       [-0.00722516,  0.15361993],
       [-0.00785781,  0.15350418],
       [-0.02865655,  0.14966376],
       [-0.02928172,  0.1495445 ],
       [-0.02970399,  0.14942282],
       [-0.03124785,  0.14896281],
       [-0.03160079,  0.14884731],
       [-0.03311488,  0.14832349],
       [-0.04643741,  0.14369722],
       [-0.04831254,  0.14301643],
       [-0.04846789,  0.14294296],
       [-0.04902343,  0.14264339],
       [-0.04980039,  0.14218488],
       [-0.05127431,  0.14122099],
       [-0.05343824,  0.13978482],
       [-0.06641953,  0.1306598 ],
       [-0.06719992,  0.13009146],
       [-0.06732267,  0.12997761],
       [-0.06842394,  0.12872382],
       [-0.06895024,  0.12808815],
       [-0.07854825,  0.11574519],
       [-0.08365013,  0.10504   ],
       [-0.0837306 ,  0.10486896],
       [-0.08384365,  0.10417084],
       [-0.08444646,  0.09768441]])

# make first and last point the same, to close the circle
s = np.concatenate([s,s[:1]]) 
y = s[:,0]
x = s[:,1]
# plot the polygon xy
plt.plot(x, y, 'b--', label='Polygon with x/y')
# plot only x values of the polygon (does not work)
plt.plot(x, np.zeros(len(x)), 'g-', linewidth=10, label='does not stretch over red dots')
# do the same, but with dots to show x values (does work)
plt.plot(x, np.zeros(len(x)), 'r.') 
# do the same, a little bit lower, but with shifted/rolled x values. 
# rolled by 1 or 2 does not help, but by 3 or 4 does.
plt.plot(np.roll(x,3), np.ones(len(x))-1.02, '-', color="lightgreen", linewidth=10, label="stretches over red dots")
# do the same again with dots to show x values
plt.plot(np.roll(x,3), np.ones(len(x))-1.02, 'r.')
plt.legend(loc='lower center').get_frame().set_alpha(1)
plt.show()

在Windows10中通过Anaconda

Python 3.5 x64。 Matplotlib是v2.0.0

Answer 1

一个0毫米宽的游泳池有多长？从理论上讲，它有一定的长度，但实际上你无法衡量它。这里也是如此，在一个维度中没有扩展的多边形可能会被渲染到任何长度。根据图形大小，缩放级别，轴范围，您会看到两个多边形都发生相同的效果。

我认为您已经通过绘制线而不是多边形找到了解决方案。这也是我的建议。

线部分未绘制

1 个答案: