56 lines
1.7 KiB
Python
56 lines
1.7 KiB
Python
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"""Load/dump geometries using the well-known binary (WKB) format
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"""
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from shapely.geos import WKBReader, WKBWriter, lgeos
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from shapely.geometry.base import geom_factory
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# Pickle-like convenience functions
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def loads(data, hex=False):
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"""Load a geometry from a WKB byte string, or hex-encoded string if
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``hex=True``.
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"""
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reader = WKBReader(lgeos)
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if hex:
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return reader.read_hex(data)
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else:
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return reader.read(data)
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def load(fp, hex=False):
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"""Load a geometry from an open file."""
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data = fp.read()
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return loads(data, hex=hex)
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def dumps(ob, hex=False, srid=None, **kw):
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"""Dump a WKB representation of a geometry to a byte string, or a
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hex-encoded string if ``hex=True``.
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Parameters
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----------
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ob : geometry
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The geometry to export to well-known binary (WKB) representation
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hex : bool
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If true, export the WKB as a hexidecimal string. The default is to
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return a binary string/bytes object.
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srid : int
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Spatial reference system ID to include in the output. The default value
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means no SRID is included.
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**kw : kwargs
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See available keyword output settings in ``shapely.geos.WKBWriter``."""
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if srid is not None:
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# clone the object and set the SRID before dumping
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geom = lgeos.GEOSGeom_clone(ob._geom)
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lgeos.GEOSSetSRID(geom, srid)
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ob = geom_factory(geom)
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kw["include_srid"] = True
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writer = WKBWriter(lgeos, **kw)
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if hex:
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return writer.write_hex(ob)
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else:
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return writer.write(ob)
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def dump(ob, fp, hex=False, **kw):
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"""Dump a geometry to an open file."""
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fp.write(dumps(ob, hex=hex, **kw))
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