64 lines
2.0 KiB
Python
64 lines
2.0 KiB
Python
from cx_Oracle import CLOB
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from django.contrib.gis.db.backends.base.adapter import WKTAdapter
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from django.contrib.gis.geos import GeometryCollection, Polygon
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class OracleSpatialAdapter(WKTAdapter):
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input_size = CLOB
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def __init__(self, geom):
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"""
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Oracle requires that polygon rings are in proper orientation. This
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affects spatial operations and an invalid orientation may cause
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failures. Correct orientations are:
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* Outer ring - counter clockwise
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* Inner ring(s) - clockwise
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"""
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if isinstance(geom, Polygon):
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if self._polygon_must_be_fixed(geom):
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geom = self._fix_polygon(geom)
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elif isinstance(geom, GeometryCollection):
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if any(isinstance(g, Polygon) and self._polygon_must_be_fixed(g) for g in geom):
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geom = self._fix_geometry_collection(geom)
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self.wkt = geom.wkt
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self.srid = geom.srid
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@staticmethod
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def _polygon_must_be_fixed(poly):
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return (
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not poly.empty and
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(
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not poly.exterior_ring.is_counterclockwise or
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any(x.is_counterclockwise for x in poly)
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)
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)
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@classmethod
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def _fix_polygon(cls, poly, clone=True):
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"""Fix single polygon orientation as described in __init__()."""
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if clone:
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poly = poly.clone()
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if not poly.exterior_ring.is_counterclockwise:
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poly.exterior_ring = list(reversed(poly.exterior_ring))
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for i in range(1, len(poly)):
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if poly[i].is_counterclockwise:
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poly[i] = list(reversed(poly[i]))
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return poly
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@classmethod
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def _fix_geometry_collection(cls, coll):
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"""
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Fix polygon orientations in geometry collections as described in
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__init__().
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"""
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coll = coll.clone()
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for i, geom in enumerate(coll):
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if isinstance(geom, Polygon):
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coll[i] = cls._fix_polygon(geom, clone=False)
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return coll
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