CODEWITHSUNDEEP
pythonpython-3.xmatplotlib
jammertheprogrammer
jammertheprogrammer

Reputation: 397

Is there a way to get the x and y coordinate of a single point in a scatter plot?

I need to get the x and y data for a point on a scatter plot. The issue is ultimately coming from the fact that when I create a scatter plot, there appears to be only one artist for all of the points. As such, when I try to get data from a PickEvent, I get the same artist no matter which point I think I am picking, and that artist only has information for ALL of the points, not just the one I want:

import numpy as np
import matplotlib.pyplot as plt

x = np.random.rand(10)
y = np.random.rand(10)

def onpick(event):
    print(event.artist.get_offsets())

plt.scatter(x,y, picker=5)
fig = plt.gcf()

cid_pick = fig.canvas.mpl_connect("pick_event", onpick)

Clicking on any of the points gives:

[[0.45112647259825556 0.4907629706037132]
 [0.33787291043006795 0.5887038833531208]
 [0.8199764461928875 0.9208354619124024]
 [0.895372081518229 0.04417158362163531]
 [0.684880991787429 0.7841477288024523]
 [0.35336419403882413 0.4661111405652941]
 [0.2931993381852086 0.9233951635623667]
 [0.14585223675195036 0.1010652948995101]
 [0.06953600296535056 0.7883191757749332]
 [0.44078084770006243 0.6173437126304926]]

In THEORY I could just use a "button_press_event" to get the x and y data of where I click, but then I would have to do some sort of closest pair algorithm in order to associate it with the specific point, and that seems kind of over-kill for what seems like a common task. My question is if there is a more "built-in" way to do this?

Upvotes: 2

Views: 1038

Answers (1)

Stef
Stef

Reputation: 30579

You can use event.ind to index into the offsets you get from get_offsets():

import numpy as np
import matplotlib.pyplot as plt

x = np.random.rand(10)
y = np.random.rand(10)

def onpick(event):
    print(event.artist.get_offsets()[event.ind][0])

plt.scatter(x,y, picker=5)
fig = plt.gcf()

cid_pick = fig.canvas.mpl_connect("pick_event", onpick)

Upvotes: 1

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