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# Authors: see git history
#
# Copyright (c) 2010 Authors
# Licensed under the GNU GPL version 3.0 or later. See the file LICENSE for details.
import math
from shapely.geometry import LineString
from shapely.geometry import Point as ShapelyPoint
def cut(line, distance, normalized=False):
""" Cuts a LineString in two at a distance from its starting point.
This is an example in the Shapely documentation.
"""
if normalized:
distance *= line.length
if distance <= 0.0:
return [None, line]
elif distance >= line.length:
return [line, None]
coords = list(ShapelyPoint(p) for p in line.coords)
traveled = 0
last_point = coords[0]
for i, p in enumerate(coords[1:], 1):
traveled += p.distance(last_point)
last_point = p
if traveled == distance:
return [
LineString(coords[:i + 1]),
LineString(coords[i:])]
if traveled > distance:
cp = line.interpolate(distance)
return [
LineString(coords[:i] + [(cp.x, cp.y)]),
LineString([(cp.x, cp.y)] + coords[i:])]
def cut_path(points, length):
"""Return a subsection of at the start of the path that is length units long.
Given a path denoted by a set of points, walk along it until we've travelled
the specified length and return a new path up to that point.
If the original path isn't that long, just return it as is.
"""
if len(points) < 2:
return points
path = LineString(points)
subpath, rest = cut(path, length)
return [Point(*point) for point in subpath.coords]
def collapse_duplicate_point(geometry):
if geometry.area < 0.01:
return geometry.representative_point()
return geometry
class Point:
def __init__(self, x, y):
self.x = x
self.y = y
def __json__(self):
return vars(self)
def __add__(self, other):
return self.__class__(self.x + other.x, self.y + other.y)
def __sub__(self, other):
return self.__class__(self.x - other.x, self.y - other.y)
def mul(self, scalar):
return self.__class__(self.x * scalar, self.y * scalar)
def __mul__(self, other):
if isinstance(other, Point):
# dot product
return self.x * other.x + self.y * other.y
elif isinstance(other, (int, float)):
return self.__class__(self.x * other, self.y * other)
else:
raise ValueError("cannot multiply %s by %s" % (type(self), type(other)))
def __neg__(self):
return self * -1
def __rmul__(self, other):
if isinstance(other, (int, float)):
return self.__mul__(other)
else:
raise ValueError("cannot multiply %s by %s" % (type(self), type(other)))
def __div__(self, other):
if isinstance(other, (int, float)):
return self * (1.0 / other)
else:
raise ValueError("cannot divide %s by %s" % (type(self), type(other)))
def __repr__(self):
return "%s(%s,%s)" % (type(self), self.x, self.y)
def length(self):
return math.sqrt(math.pow(self.x, 2.0) + math.pow(self.y, 2.0))
def distance(self, other):
return (other - self).length()
def unit(self):
return self.mul(1.0 / self.length())
def rotate_left(self):
return self.__class__(-self.y, self.x)
def rotate(self, angle):
return self.__class__(self.x * math.cos(angle) - self.y * math.sin(angle), self.y * math.cos(angle) + self.x * math.sin(angle))
def as_int(self):
return self.__class__(int(round(self.x)), int(round(self.y)))
def as_tuple(self):
return (self.x, self.y)
def __getitem__(self, item):
return self.as_tuple()[item]
def __len__(self):
return 2
def line_string_to_point_list(line_string):
return [Point(*point) for point in line_string.coords]
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