Coverage for pyguymer3/geo/extract_lines.py: 35%
52 statements
« prev ^ index » next coverage.py v7.10.3, created at 2025-08-16 08:31 +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.extend(
64 extract_lines(
65 item,
66 onlyValid = onlyValid,
67 )
68 )
70 # Return answer ...
71 return lines
73 # Check type ...
74 if isinstance(shape, shapely.geometry.point.Point):
75 return []
77 # Check type ...
78 if isinstance(shape, shapely.geometry.multipoint.MultiPoint):
79 return []
81 # Check type ...
82 if isinstance(shape, shapely.geometry.polygon.LinearRing):
83 # Just return the answer if the user doesn't want any checks ...
84 if not onlyValid:
85 # Skip bad LineStrings ...
86 if shape.is_empty:
87 return []
89 # Return answer ...
90 return [shape]
92 # Check if it is valid ...
93 if shape.is_valid:
94 # Skip bad LineStrings ...
95 if shape.is_empty:
96 return []
98 # Return answer ...
99 return [shape]
101 # Return answer ...
102 return []
104 # Check type ...
105 if isinstance(shape, shapely.geometry.linestring.LineString):
106 # Just return the answer if the user doesn't want any checks ...
107 if not onlyValid:
108 # Skip bad LineStrings ...
109 if shape.is_empty:
110 return []
112 # Return answer ...
113 return [shape]
115 # Check if it is valid ...
116 if shape.is_valid:
117 # Skip bad LineStrings ...
118 if shape.is_empty:
119 return []
121 # Return answer ...
122 return [shape]
124 # Return answer ...
125 return []
127 # Check type ...
128 if isinstance(shape, shapely.geometry.multilinestring.MultiLineString):
129 # Initialize list ...
130 lines = []
132 # Loop over LineStrings ...
133 for line in shape.geoms:
134 # Add lists together ...
135 lines.extend(
136 extract_lines(
137 line,
138 onlyValid = onlyValid,
139 )
140 )
142 # Return answer ...
143 return lines
145 # Check type ...
146 if isinstance(shape, shapely.geometry.polygon.Polygon):
147 return []
149 # Check type ...
150 if isinstance(shape, shapely.geometry.multipolygon.MultiPolygon):
151 return []
153 # Check type ...
154 if isinstance(shape, shapely.geometry.collection.GeometryCollection):
155 # Initialize list ...
156 lines = []
158 # Loop over geometries ...
159 for geom in shape.geoms:
160 # Add lists together ...
161 lines.extend(
162 extract_lines(
163 geom,
164 onlyValid = onlyValid,
165 )
166 )
168 # Return answer ...
169 return lines
171 # **************************************************************************
173 raise TypeError(f"\"shape\" is an unexpected type ({repr(type(shape))})") from None