Viewing file:  adapter.py (2 KB) -rw-r--r--
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from cx_Oracle import CLOB
from django.contrib.gis.db.backends.base.adapter import WKTAdapter
from django.contrib.gis.geos import GeometryCollection, Polygon
class OracleSpatialAdapter(WKTAdapter):
input_size = CLOB
def __init__(self, geom):
"""
Oracle requires that polygon rings are in proper orientation. This
affects spatial operations and an invalid orientation may cause
failures. Correct orientations are:
* Outer ring - counter clockwise
* Inner ring(s) - clockwise
"""
if isinstance(geom, Polygon):
if self._polygon_must_be_fixed(geom):
geom = self._fix_polygon(geom)
elif isinstance(geom, GeometryCollection):
if any(isinstance(g, Polygon) and self._polygon_must_be_fixed(g) for g in geom):
geom = self._fix_geometry_collection(geom)
self.wkt = geom.wkt
self.srid = geom.srid
@staticmethod
def _polygon_must_be_fixed(poly):
return (
not poly.empty and
(
not poly.exterior_ring.is_counterclockwise or
any(x.is_counterclockwise for x in poly)
)
)
@classmethod
def _fix_polygon(cls, poly, clone=True):
"""Fix single polygon orientation as described in __init__()."""
if clone:
poly = poly.clone()
if not poly.exterior_ring.is_counterclockwise:
poly.exterior_ring = list(reversed(poly.exterior_ring))
for i in range(1, len(poly)):
if poly[i].is_counterclockwise:
poly[i] = list(reversed(poly[i]))
return poly
@classmethod
def _fix_geometry_collection(cls, coll):
"""
Fix polygon orientations in geometry collections as described in
__init__().
"""
coll = coll.clone()
for i, geom in enumerate(coll):
if isinstance(geom, Polygon):
coll[i] = cls._fix_polygon(geom, clone=False)
return coll
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