[postgis-devel] [PostGIS] #450: ST_Area(geography) returns wrong result for objects crossing dateline
PostGIS
trac at osgeo.org
Thu Feb 25 05:34:40 PST 2010
#450: ST_Area(geography) returns wrong result for objects crossing dateline
---------------------+------------------------------------------------------
Reporter: pramsey | Owner: pramsey
Type: defect | Status: new
Priority: high | Milestone: PostGIS 1.5.1
Component: postgis | Version: 1.5.X
Keywords: |
---------------------+------------------------------------------------------
http://postgis.refractions.net/pipermail/postgis-users/2010-
February/025984.html
A box that doesn't cross the dateline returns a good result:
{{{
g4wd=# select st_area(g)/1000000, st_area(transform(geometry(g), 4326)),
astext(geometry(g)) from (select 'POLYGON((178.5 2, 178.5 1, 179.5 1,
179.5
2, 178.5 2))'::geography) as foo(g);
?column? | st_area | astext
-----------------+---------+----------------------------------------------------
12304.814950073 | 1 | POLYGON((178.5 2,178.5 1,179.5 1,179.5
2,178.5
2))
(1 row)
}}}
But the same box s
hifted over the dateline returns a bad result.
{{{g4wd=# select st_area(g)/1000000, st_area(transform(geometry(g),
4326)),
astext(geometry(g)) from (select 'POLYGON((179.5 2, 179.5 1, -179.5 1,
-179.5 2, 179.5 2))'::geography) as foo(g);
?column? | st_area | astext
------------------+---------+------------------------------------------------------
55910.8880691158 | 359 | POLYGON((179.5 2,179.5 1,-179.5 1,-179.5
2,179.5 2))
(1 row)
}}}
--
Ticket URL: <http://trac.osgeo.org/postgis/ticket/450>
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