Calculating the distance between the furthest vertex of a Voronoi polygon and the point from which it was generated

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I need to calculate the distance between the furthest vertex of a Voronoi polygon and the point that generated it. I need to calculate this distance for all Voronoi polygons.

Is there a way to do it automatically in Python?

To generate the Polygon, I used Scipi. Do you have any tips or hints for me?

voronoi python
1 Answers

Something like this could work:

import numpy as np
import matplotlib.pyplot as plt
from scipy.spatial import Voronoi, voronoi_plot_2d, distance


points = np.random.uniform(0, 100, size=(10, 2))
vor = Voronoi(points)
voronoi_plot_2d(vor)

dists = []

for i,point in enumerate(points):

    # get nearby vertices
    ridges = np.where(vor.ridge_points == i)[0]
    vertex_set = set(np.array(vor.ridge_vertices)[ridges, :].ravel())
    region = [x for x in vor.regions if set(x) == vertex_set][0]
    region = [x for x in region if x != -1] # remove outliers
    polygon = vor.vertices[region]
    if len(polygon) < 1:
        continue

    # calc distance of every vertex to the initial point
    distances = distance.cdist([point], polygon).T
    max_dist_idx = np.argmax(distances)
    max_dist = distances[max_dist_idx]
    dists.append(max_dist)

    # just for visuals
    xvals = [point[0], polygon[max_dist_idx][0]]
    yvals = [point[1], polygon[max_dist_idx][1]]
    plt.plot(xvals,yvals,'r-')
    # do stuff with that info

plt.show()

The method to match polygons with the enclosed point was posted here: https://stackoverflow.com/a/47316980/9173710

user_91737100
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