Coverage for pyguymer3/geo/extract_lines.py: 35%
52 statements
« prev ^ index » next coverage.py v7.9.2, created at 2025-07-08 18:47 +0000
1#!/usr/bin/env python3
3# Define function ...
4def extract_lines(
5 shape,
6 /,
7 *,
8 onlyValid = False,
9):
10 """Extract the LineStrings from the shape
12 This function accepts any Shapely geometry and returns a flat list of all of
13 the LineStrings contained within.
15 Parameters
16 ----------
17 shape : list, shapely.geometry.point.Point, shapely.geometry.multipoint.MultiPoint, shapely.geometry.polygon.LinearRing, shapely.geometry.linestring.LineString, shapely.geometry.multilinestring.MultiLineString, shapely.geometry.polygon.Polygon, shapely.geometry.multipolygon.MultiPolygon, shapely.geometry.collection.GeometryCollection
18 the Shapely geometry
19 onlyValid : bool, optional
20 only return valid LineStrings (checks for validity can take a while, if
21 being called often)
23 Returns
24 -------
25 lines : list of shapely.geometry.linestring.LineString
26 a flat list of all of the LineStrings
28 Notes
29 -----
30 To pass GeoJSON objects you must first convert them to Shapely objects by
31 doing something like ``shape = shapely.geometry.shape(shape)``.
33 Copyright 2017 Thomas Guymer [1]_
35 References
36 ----------
37 .. [1] PyGuymer3, https://github.com/Guymer/PyGuymer3
38 """
40 # Import special modules ...
41 try:
42 import shapely
43 import shapely.geometry
44 except:
45 raise Exception("\"shapely\" is not installed; run \"pip install --user Shapely\"") from None
47 # **************************************************************************
49 # Check type ...
50 if shape is None:
51 return []
53 # **************************************************************************
55 # Check type ...
56 if isinstance(shape, list):
57 # Initialize list ...
58 lines = []
60 # Loop over items ...
61 for item in shape:
62 # Add lists together ...
63 lines += extract_lines(item, onlyValid = onlyValid)
65 # Return answer ...
66 return lines
68 # Check type ...
69 if isinstance(shape, shapely.geometry.point.Point):
70 return []
72 # Check type ...
73 if isinstance(shape, shapely.geometry.multipoint.MultiPoint):
74 return []
76 # Check type ...
77 if isinstance(shape, shapely.geometry.polygon.LinearRing):
78 # Just return the answer if the user doesn't want any checks ...
79 if not onlyValid:
80 # Skip bad LineStrings ...
81 if shape.is_empty:
82 return []
84 # Return answer ...
85 return [shape]
87 # Check if it is valid ...
88 if shape.is_valid:
89 # Skip bad LineStrings ...
90 if shape.is_empty:
91 return []
93 # Return answer ...
94 return [shape]
96 # Return answer ...
97 return []
99 # Check type ...
100 if isinstance(shape, shapely.geometry.linestring.LineString):
101 # Just return the answer if the user doesn't want any checks ...
102 if not onlyValid:
103 # Skip bad LineStrings ...
104 if shape.is_empty:
105 return []
107 # Return answer ...
108 return [shape]
110 # Check if it is valid ...
111 if shape.is_valid:
112 # Skip bad LineStrings ...
113 if shape.is_empty:
114 return []
116 # Return answer ...
117 return [shape]
119 # Return answer ...
120 return []
122 # Check type ...
123 if isinstance(shape, shapely.geometry.multilinestring.MultiLineString):
124 # Initialize list ...
125 lines = []
127 # Loop over LineStrings ...
128 for line in shape.geoms:
129 # Add lists together ...
130 lines += extract_lines(line, onlyValid = onlyValid)
132 # Return answer ...
133 return lines
135 # Check type ...
136 if isinstance(shape, shapely.geometry.polygon.Polygon):
137 return []
139 # Check type ...
140 if isinstance(shape, shapely.geometry.multipolygon.MultiPolygon):
141 return []
143 # Check type ...
144 if isinstance(shape, shapely.geometry.collection.GeometryCollection):
145 # Initialize list ...
146 lines = []
148 # Loop over geometries ...
149 for geom in shape.geoms:
150 # Add lists together ...
151 lines += extract_lines(geom, onlyValid = onlyValid)
153 # Return answer ...
154 return lines
156 # **************************************************************************
158 raise TypeError(f"\"shape\" is an unexpected type ({repr(type(shape))})") from None