PostGIS - 某些多重多边形会导致“BOOM！”无法生成外部点！”
我试图表示一个跨越 180 度经度的矩形区域。有关更多背景信息，请参阅在PostGIS中，大于半个世界的多边形被视为相反
这是我的测试用例：
from django.contrib.gis.geos import Polygon, MultiPolygon
from my_project.my_app.models import Photo
a = Polygon.from_bbox((30, -80, 180, 80)) # the part to the east of 180
b = Polygon.from_bbox((-180, -80, -160, 80)) # a part to the west of 180
c = Polygon.from_bbox((-180, -80, -100, 80)) # a larger part to the west of 180
ok = MultiPolygon(a,b)
ok2 = MultiPolygon(c)
boom = MultiPolygon(a,c)
# This works
Photo.objects.filter(location__coveredby=ok)[:1]
# This also works so c is ok
Photo.objects.filter(location__coveredby=ok2)[:1]
# This gives "BOOM! Could not generate outside point!"
Photo.objects.filter(location__coveredby=boom)[:1]
# splitting c doesn't help
c1 = Polygon.from_bbox((-180, -80, -140, 80))
c2 = Polygon.from_bbox((-140, -80, -100, 80))
test = MultiPolygon(a,c1,c2)
Photo.objects.filter(location__coveredby=test)[:1]
# BOOM! Could not generate outside point!
通过更改我可以让这个错误来来去去。 例如，(-180, -80, x, 80) 适用于 x <= -140 的情况。对于每个数字都有一个这样的阈值，但我找不到模式。对于具有相同面积的盒子，有些可以工作，有些则不行。对于宽度相同的盒子，有些可以使用，有些则不行。
我可以查看正在生成的 SQL，但这些区域以二进制 (EWKB) 表示，我不知道如何读取它。
谁能解释一下吗？
I'm trying to represent a rectangular area which crosses 180 degrees longitude. For more background see In PostGIS a polygon bigger than half the world is treated as it's opposite
Here's my test case:
from django.contrib.gis.geos import Polygon, MultiPolygon
from my_project.my_app.models import Photo
a = Polygon.from_bbox((30, -80, 180, 80)) # the part to the east of 180
b = Polygon.from_bbox((-180, -80, -160, 80)) # a part to the west of 180
c = Polygon.from_bbox((-180, -80, -100, 80)) # a larger part to the west of 180
ok = MultiPolygon(a,b)
ok2 = MultiPolygon(c)
boom = MultiPolygon(a,c)
# This works
Photo.objects.filter(location__coveredby=ok)[:1]
# This also works so c is ok
Photo.objects.filter(location__coveredby=ok2)[:1]
# This gives "BOOM! Could not generate outside point!"
Photo.objects.filter(location__coveredby=boom)[:1]
# splitting c doesn't help
c1 = Polygon.from_bbox((-180, -80, -140, 80))
c2 = Polygon.from_bbox((-140, -80, -100, 80))
test = MultiPolygon(a,c1,c2)
Photo.objects.filter(location__coveredby=test)[:1]
# BOOM! Could not generate outside point!
By changing the numbers I can make this error come and go.
(-180, -80, x, 80) works where x <= -140 for example. For every number there is a threshold like this but I can't find a pattern. For boxes with the same area, some will work and others not. For boxes with the same width some will work and others not.
I can look at the SQL being generated but the areas are represented in binary (EWKB) and I'm not sure how to read it.
Can anyone explain this?
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问完这个问题后，我发现了 gis.stackexchange.com，所以我也在那里问了。在那里好心人的帮助下，我找到了问题所在（我认为）和解决方案。
看：
<一href="https://gis.stackexchange.com/questions/9217/postgis-certain-multipolygons-cause-boom-could-not-generate-outside-point/9257#9257 ">https://gis.stackexchange.com/questions/9217/postgis-certain-multipolygons-cause-boom-could-not-generate-outside-point/9257#9257
After asking this question I found out about gis.stackexchange.com, so I asked there too. With the help of the good folks there I found out what the problem is (I think) and a solution.
See:
https://gis.stackexchange.com/questions/9217/postgis-certain-multipolygons-cause-boom-could-not-generate-outside-point/9257#9257