[postgis-tickets] [PostGIS] #4951: Geometries returning zero area with PostGIS 3.1.2

[PostGIS]

#4951: Geometries returning zero area with PostGIS 3.1.2
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 Reporter:  mboeringa  |      Owner:  pramsey
     Type:  defect     |     Status:  new
 Priority:  medium     |  Milestone:  PostGIS 3.1.3
Component:  postgis    |    Version:  3.1.x
 Keywords:             |
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 I am running into an issue with two of OpenStreetMap's polygon geomtries
 returning a zero area for the following PostGIS SQL clause:

 ST_Area(ST_ConvexHull(ST_Transform(way,4326))::geography,true)

 Note that the data was imported using osm2pgsql, with the data stored in
 WGS1984, not Web Mercator.

 The two relations that cause the issue are:

 https://www.openstreetmap.org/relation/2186646

 https://www.openstreetmap.org/relation/3394113

 One represents "Antarctica", the other the "Ross Dependency".

 Note that both relations appear to be quite old (years), and I am therefor
 pretty sure I have processed the exact same geometries previously without
 issues with older versions of PostGIS after planet import. Note also that
 both geometries test as valid with "ST_Isvalid(way)" after import using
 osm2pgsql.

 Has something changed in the latest PostGIS 3.1.2 that might explain this
 result, e.g. especially related to the "::geography" cast or the
 "ST_ConvexHull" statement?

 Of course, in the way these geometries wrap the globe, they may represent
 a challenge, but as said, I am pretty sure I must have processed the same
 geometries without issues in previous releases of PostGIS.

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Ticket URL: <https://trac.osgeo.org/postgis/ticket/4951>
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