[postgis-users] TR: strange behavior of ST_Area(geography)

[Ben Madin]

Works for me ... from the small sample size, it would appear that the
version of GDAL you have compiled against (I am using 2.1.3, as is Olivier)
might need to be updated from the 2013 release.

hth

Ben

On 16 October 2017 at 23:48, Paul Ramsey <pramsey at cleverelephant.ca> wrote:

> Werks fer me also:
>
>  st_equals | eq_area | geog1 | geog2 | geog3 | geom
> -----------+---------+-------+-------+-------+------
>  t         | t       | t     | t     | t     | t
>
>
> On Sun, Oct 15, 2017 at 6:07 AM, IIDA Tetsushi <hogeman at gmail.com> wrote:
>
>> thank you, Olivier.
>>
>> sorry, i forgot to describe my environment.
>> ----------------------------------------------------------------
>>  PostgreSQL 9.6.3 on x86_64-pc-linux-gnu, compiled by gcc (Debian
>> 4.9.2-10) 4.9.2, 64-bit
>>  POSTGIS="2.3.2 r15302" GEOS="3.4.2-CAPI-1.8.2 r3921" PROJ="Rel.
>> 4.8.0, 6 March 2012" GDAL="GDAL 1.10.1,
>>  released 2013/08/26" LIBXML="2.9.1" LIBJSON="0.11.99" RASTER
>>
>> (docker image "mdillon/postgis")
>>
>>
>> 2017-10-15 21:34 GMT+09:00 Olivier Leprêtre <o.lepretre at gmail.com>:
>> > 9.6 and
>> > "POSTGIS="2.3.2 r15302" GEOS="3.6.1-CAPI-1.10.1 r4317" PROJ="Rel.
>> 4.9.1, 04 March 2015" GDAL="GDAL 2.1.3, released 2017/20/01" LIBXML="2.7.8"
>> LIBJSON="0.12" TOPOLOGY RASTER"
>> >
>> > -----Message d'origine-----
>> > De : Olivier Leprêtre [mailto:o.lepretre at gmail.com]
>> > Envoyé : dimanche 15 octobre 2017 14:33
>> > À : 'PostGIS Users Discussion'
>> > Objet : RE: [postgis-users] strange behavior of ST_Area(geography)
>> >
>> > I tested your query with 9.6 all tests return true.
>> >
>> > Olivier
>> >
>> > -----Message d'origine-----
>> > De : postgis-users [mailto:postgis-users-bounces at lists.osgeo.org] De
>> la part de IIDA Tetsushi Envoyé : dimanche 15 octobre 2017 13:42 À :
>> postgis-users at lists.osgeo.org Objet : [postgis-users] strange behavior
>> of ST_Area(geography)
>> >
>> > Hi,
>> >
>> > These polygons have the same shape but orientation.
>> >
>> > --- my query -----
>> > WITH poly AS (
>> >  SELECT
>> >   ST_SetSRID(ST_GeomFromText(
>> >    'POLYGON((138.002 37.001, 138.003 37.0010, 138.003 37.0013, 138.002
>> 37.001))'
>> >    ),4326) g1,
>> >   ST_SetSRID(ST_GeomFromText(
>> >    'POLYGON((138.002 37.001, 138.003 37.0013, 138.003 37.0010, 138.002
>> 37.001))'
>> >    ),4326) g2
>> > )
>> > SELECT ST_Equals(g1,g2),
>> >  ST_Area(g1)                     = ST_Area(g2) AS eq_area,
>> >  ST_Area(g1::geography)          = ST_Area(g2::geography) AS geog1,
>> >  ST_Area(g1::geography, false)   = ST_Area(g2::geography, false) AS
>> geog2,
>> >  ST_Area(g1::geography)          = ST_Area(ST_Reverse(g2)::geography)
>> AS geog3,
>> >  ST_Area(ST_Transform(g1,32654)) = ST_Area(ST_Transform(g2,32654)) AS
>> geom  FROM poly;
>> >
>> > ----- output -----
>> >
>> >  st_equals | eq_area | geog1 | geog2 | geog3 | geom
>> > -----------+---------+-------+-------+-------+------
>> >  t         | t       | f     | t     | t     | t
>> >
>> >
>> > I expected all these tests return true.
>> > Is this behavior by spec?
>> >
>> > Thanks
>> >
>> > --
>> > hogeman
>> > _______________________________________________
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>> > https://lists.osgeo.org/mailman/listinfo/postgis-users
>> >
>> >
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>>
>>
>>
>> --
>> Iida, Tetsushi
>> 飯田 哲士
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>
>
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