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"""
@package iscatt.utils
@brief Misc utilities for iscatt
(C) 2020 by the GRASS Development Team
This program is free software under the GNU General Public License
(>=v2). Read the file COPYING that comes with GRASS for details.
@author Nicklas Larsson <n_larsson yahoo com>
"""
import numpy as np
# Code originate from matplotlib
# https://matplotlib.org/3.0.0/_modules/matplotlib/mlab.html#dist
def dist(x, y):
"""
Return the distance between two points.
"""
d = x - y
return np.sqrt(np.dot(d, d))
# Code originate from matplotlib
# https://matplotlib.org/3.0.0/_modules/matplotlib/mlab.html#dist_point_to_segment
def dist_point_to_segment(p, s0, s1):
"""
Get the distance of a point to a segment.
*p*, *s0*, *s1* are *xy* sequences
This algorithm from
http://geomalgorithms.com/a02-_lines.html
"""
p = np.asarray(p, float)
s0 = np.asarray(s0, float)
s1 = np.asarray(s1, float)
v = s1 - s0
w = p - s0
c1 = np.dot(w, v)
if c1 <= 0:
return dist(p, s0)
c2 = np.dot(v, v)
if c2 <= c1:
return dist(p, s1)
b = c1 / c2
pb = s0 + b * v
return dist(p, pb)
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