Coverage for pyguymer3/geo/extract_polys.py: 54%
46 statements
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1#!/usr/bin/env python3
3# Define function ...
4def extract_polys(
5 shape,
6 /,
7 *,
8 onlyValid = False,
9 repair = False,
10):
11 """Extract the Polygons from the shape
13 This function accepts any Shapely geometry and returns a flat list of all of
14 the Polygons contained within.
16 Parameters
17 ----------
18 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
19 the Shapely geometry
20 onlyValid : bool, optional
21 only return valid Polygons (checks for validity can take a while, if
22 being called often)
23 repair : bool, optional
24 attempt to repair invalid Polygons
26 Returns
27 -------
28 polys : list of shapely.geometry.polygon.Polygon
29 a flat list of all of the Polygons
31 Note
32 ----
33 To pass GeoJSON objects you must first convert them to Shapely objects by
34 doing something like ``shape = shapely.geometry.shape(shape)``.
36 Copyright 2017 Thomas Guymer [1]_
38 References
39 ----------
40 .. [1] PyGuymer3, https://github.com/Guymer/PyGuymer3
41 """
43 # Import special modules ...
44 try:
45 import shapely
46 import shapely.geometry
47 except:
48 raise Exception("\"shapely\" is not installed; run \"pip install --user Shapely\"") from None
50 # **************************************************************************
52 # Check type ...
53 if shape is None:
54 return []
56 # **************************************************************************
58 # Check type ...
59 if isinstance(shape, list):
60 # Initialize list ...
61 polys = []
63 # Loop over items ...
64 for item in shape:
65 # Add lists together ...
66 polys.extend(
67 extract_polys(
68 item,
69 onlyValid = onlyValid,
70 repair = repair,
71 )
72 )
74 # Return answer ...
75 return polys
77 # Check type ...
78 if isinstance(shape, shapely.geometry.point.Point):
79 return []
81 # Check type ...
82 if isinstance(shape, shapely.geometry.multipoint.MultiPoint):
83 return []
85 # Check type ...
86 if isinstance(shape, shapely.geometry.polygon.LinearRing):
87 return []
89 # Check type ...
90 if isinstance(shape, shapely.geometry.linestring.LineString):
91 return []
93 # Check type ...
94 if isinstance(shape, shapely.geometry.multilinestring.MultiLineString):
95 return []
97 # Check type ...
98 if isinstance(shape, shapely.geometry.polygon.Polygon):
99 # Just return the answer if the user doesn't want any checks or fixes ...
100 if not onlyValid:
101 # Skip bad Polygons ...
102 if shape.is_empty:
103 return []
105 # Return answer ...
106 return [shape]
108 # Check if it is valid ...
109 if shape.is_valid:
110 # Skip bad Polygons ...
111 if shape.is_empty:
112 return []
114 # Return answer ...
115 return [shape]
117 # Check if the user wants to attempt to fix it ...
118 if repair:
119 # Try to repair it and return answer ...
120 return extract_polys(
121 shape.buffer(0.0),
122 onlyValid = onlyValid,
123 repair = repair,
124 )
126 # Return answer ...
127 return []
129 # Check type ...
130 if isinstance(shape, shapely.geometry.multipolygon.MultiPolygon):
131 # Initialize list ...
132 polys = []
134 # Loop over Polygons ...
135 for poly in shape.geoms:
136 # Add lists together ...
137 polys.extend(
138 extract_polys(
139 poly,
140 onlyValid = onlyValid,
141 repair = repair,
142 )
143 )
145 # Return answer ...
146 return polys
148 # Check type ...
149 if isinstance(shape, shapely.geometry.collection.GeometryCollection):
150 # Initialize list ...
151 polys = []
153 # Loop over geometries ...
154 for geom in shape.geoms:
155 # Add lists together ...
156 polys.extend(
157 extract_polys(
158 geom,
159 onlyValid = onlyValid,
160 repair = repair,
161 )
162 )
164 # Return answer ...
165 return polys
167 # **************************************************************************
169 raise TypeError(f"\"shape\" is an unexpected type ({repr(type(shape))})") from None