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Code Issues 25 Releases Wiki Activity

Refs #26789 -- Fixed output of WKBWriter for empty points and polygons.

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This commit is contained in:
Sergey Fedoseev 2016-12-01 14:26:12 +05:00 committed by Tim Graham
parent 181f492ad0
commit b90d72facf
2 changed files with 66 additions and 3 deletions
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28
django/contrib/gis/geos/prototypes/io.py
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@ -226,13 +226,37 @@ class WKBWriter(IOBase):
super(WKBWriter, self).__init__()
self.outdim = dim
def _handle_empty_point(self, geom):
from django.contrib.gis.geos import Point
if isinstance(geom, Point) and geom.empty:
if self.srid:
# PostGIS uses POINT(NaN NaN) for WKB representation of empty
# points. Use it for EWKB as it's a PostGIS specific format.
# https://trac.osgeo.org/postgis/ticket/3181
geom = Point(float('NaN'), float('NaN'), srid=geom.srid)
else:
raise ValueError('Empty point is not representable in WKB.')
return geom
def write(self, geom):
"Returns the WKB representation of the given geometry."
return six.memoryview(wkb_writer_write(self.ptr, geom.ptr, byref(c_size_t())))
from django.contrib.gis.geos import Polygon
geom = self._handle_empty_point(geom)
wkb = wkb_writer_write(self.ptr, geom.ptr, byref(c_size_t()))
if isinstance(geom, Polygon) and geom.empty:
# Fix GEOS output for empty polygon.
# See https://trac.osgeo.org/geos/ticket/680.
wkb = wkb[:-8] + b'\0' * 4
return six.memoryview(wkb)
def write_hex(self, geom):
"Returns the HEXEWKB representation of the given geometry."
return wkb_writer_write_hex(self.ptr, geom.ptr, byref(c_size_t()))
from django.contrib.gis.geos.polygon import Polygon
geom = self._handle_empty_point(geom)
wkb = wkb_writer_write_hex(self.ptr, geom.ptr, byref(c_size_t()))
if isinstance(geom, Polygon) and geom.empty:
wkb = wkb[:-16] + b'0' * 8
return wkb
# ### WKBWriter Properties ###

41
tests/gis_tests/geos_tests/test_io.py
View File

@ -4,7 +4,8 @@ import binascii
from unittest import skipUnless
from django.contrib.gis.geos import (
HAS_GEOS, GEOSGeometry, Point, WKBReader, WKBWriter, WKTReader, WKTWriter,
HAS_GEOS, GEOSGeometry, Point, Polygon, WKBReader, WKBWriter, WKTReader,
WKTWriter,
)
from django.test import SimpleTestCase
from django.utils.six import memoryview
@ -155,3 +156,41 @@ class GEOSIOTest(SimpleTestCase):
with self.assertRaisesMessage(AttributeError, 'WKT output rounding precision must be '):
wkt_w.precision = 'potato'
def test_empty_point_wkb(self):
p = Point(srid=4326)
wkb_w = WKBWriter()
wkb_w.srid = False
with self.assertRaisesMessage(ValueError, 'Empty point is not representable in WKB.'):
wkb_w.write(p)
with self.assertRaisesMessage(ValueError, 'Empty point is not representable in WKB.'):
wkb_w.write_hex(p)
wkb_w.srid = True
for byteorder, hex in enumerate([
b'0020000001000010E67FF80000000000007FF8000000000000',
b'0101000020E6100000000000000000F87F000000000000F87F',
]):
wkb_w.byteorder = byteorder
self.assertEqual(wkb_w.write_hex(p), hex)
self.assertEqual(GEOSGeometry(wkb_w.write_hex(p)), p)
self.assertEqual(wkb_w.write(p), memoryview(binascii.a2b_hex(hex)))
self.assertEqual(GEOSGeometry(wkb_w.write(p)), p)
def test_empty_polygon_wkb(self):
p = Polygon(srid=4326)
p_no_srid = Polygon()
wkb_w = WKBWriter()
wkb_w.srid = True
for byteorder, hexes in enumerate([
(b'000000000300000000', b'0020000003000010E600000000'),
(b'010300000000000000', b'0103000020E610000000000000'),
]):
wkb_w.byteorder = byteorder
for srid, hex in enumerate(hexes):
wkb_w.srid = srid
self.assertEqual(wkb_w.write_hex(p), hex)
self.assertEqual(GEOSGeometry(wkb_w.write_hex(p)), p if srid else p_no_srid)
self.assertEqual(wkb_w.write(p), memoryview(binascii.a2b_hex(hex)))
self.assertEqual(GEOSGeometry(wkb_w.write(p)), p if srid else p_no_srid)