Matplotlib plot spaces separated data array

Question

What's the easiest way to format this array data so that I can connect the points on the graph iterating, assuming each line contains x and y coordinates of a single point?

import matplotlib.pyplot as plt
(...)

<class 'numpy.ndarray'>
[-22.58343371   7.97162262]
[-49.08400669 -28.64111278]
[-71.47754547 -25.78248676]
[-46.27120899 -21.72541444]
[ 43.6158669  109.61815799]
[-22.58343371   7.97162262]

(...)

plt.plot(x, y, color='orange')

Sorry, below is almost complete code (order is calculated by another alghoritm) corrected thanks to Quang Hoang's comment. This is obviously part of the solution to the well known tsp problem. The point, of course, is to connect the points according to the correct order in the list which in this case is: (0, 2, 1, 3, 4, 0).

from sklearn.decomposition import PCA
import matplotlib.pyplot as plt
import numpy as np

n = 5
order = (0, 2, 1, 3, 4, 0)

distances = [[0, 39, 22, 59, 54, 33, 57, 32, 89, 73, 29, 46],
             [39, 0, 20, 20, 81, 8, 49, 64, 63, 84, 10, 61],
             [22, 20, 0, 39, 74, 18, 60, 44, 71, 73, 11, 46],
             [59, 20, 39, 0, 93, 27, 51, 81, 48, 80, 30, 69],
             [54, 81, 74, 93, 0, 73, 43, 56, 104, 76, 76, 77],
             [33, 8, 18, 27, 73, 0, 45, 61, 71, 88, 8, 63],
             [57, 49, 60, 51, 43, 45, 0, 85, 88, 115, 52, 103],
             [32, 64, 44, 81, 56, 61, 85, 0, 74, 43, 55, 23],
             [89, 63, 71, 48, 104, 71, 88, 74, 0, 38, 69, 51],
             [73, 84, 73, 80, 76, 88, 115, 43, 38, 0, 81, 28],
             [29, 10, 11, 30, 76, 8, 52, 55, 69, 81, 0, 55],
             [46, 61, 46, 69, 77, 63, 103, 23, 51, 28, 55, 0]]

pca = PCA(n_components=2)
coord = pca.fit_transform(distances[:n])

plt.scatter(coord[:,0], coord[:,1])

for i in coord:
    x = np.where(coord == i)
    plt.annotate((x[0][0]) ,i, color='red')

for j in order:
    print(coord[j])
    plt.plot(coord[:,0], coord[:,1], color='orange')
plt.show()

Please post the full code. Also, what do you mean by "connect the points on the graph iterating"? — Kapocsi
– Kapocsi, Commented Dec 17, 2020 at 17:25

uhlik · Accepted Answer · 2020-12-18 12:46:42Z

Sometimes, after many hours, things feel more difficult than they are:) Thank's a lot Kapocsi! Working solution below:

from sklearn.decomposition import PCA
import matplotlib.pyplot as plt
import numpy as np

n = 5
order = [0, 2, 1, 3, 4, 0]

distances = [[0, 39, 22, 59, 54, 33, 57, 32, 89, 73, 29, 46],
             [39, 0, 20, 20, 81, 8, 49, 64, 63, 84, 10, 61],
             [22, 20, 0, 39, 74, 18, 60, 44, 71, 73, 11, 46],
             [59, 20, 39, 0, 93, 27, 51, 81, 48, 80, 30, 69],
             [54, 81, 74, 93, 0, 73, 43, 56, 104, 76, 76, 77],
             [33, 8, 18, 27, 73, 0, 45, 61, 71, 88, 8, 63]]

pca = PCA(n_components=2)
coord = pca.fit_transform(distances[:n])

plt.scatter(coord[:,0], coord[:,1])

for i in coord:
    x = np.where(coord == i)
    plt.annotate((x[0][0]) ,i, color='red')

x = coord[order]
print(x)

plt.plot(x[:, 0], x[:, 1], color='orange', marker='o', linestyle='-')
plt.show()

Kapocsi · Accepted Answer · 2020-12-17 17:48:33Z

0

You likely need to sort the data to get the visualization you want:

import numpy as np
import matplotlib.pyplot as plt


a = np.array([[-22.58343371,   7.97162262],
              [-49.08400669, -28.64111278],
              [-71.47754547, -25.78248676],
              [-46.27120899, -21.72541444],
              [ 43.6158669 , 109.61815799],
              [-22.58343371,   7.97162262]])


order = a[:, 0].argsort()
plt.plot(a[order, 0], a[order, 1], color='orange', marker='o', linestyle='-')
plt.show()

If you don't sort it, you will end up with something like this:

import numpy as np
import matplotlib.pyplot as plt


a = np.array([[-22.58343371,   7.97162262],
              [-49.08400669, -28.64111278],
              [-71.47754547, -25.78248676],
              [-46.27120899, -21.72541444],
              [ 43.6158669 , 109.61815799],
              [-22.58343371,   7.97162262]])

plt.plot(a[:, 0], a[:, 1], color='orange', marker='o', linestyle='-')
plt.show()

answered Dec 17, 2020 at 17:48

Kapocsi

1,0327 silver badges17 bronze badges

1 Comment

uhlik Over a year ago

Thank you Kapocsi, but I would like to plot lines in given order.

Collectives™ on Stack Overflow

Matplotlib plot spaces separated data array

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related