[postgis-users] ST_length_spheroid and ST_distance_spheroid

[Paul Ramsey]

If you change the 180 to 179 do the results match up again? (ie, do
any distance less than a perfect half-sphere?)

P

On Thu, Apr 22, 2010 at 8:06 AM, Olivier Courtin
<olivier.courtin at oslandia.com> wrote:
>
> On Apr 22, 2010, at 4:49 PM, Paul Ramsey wrote:
>
>> They don't, at least for me:
>>
>> postgis14=# select st_distance_spheroid(geomfromtext('POINT(0 0)',4326),
>> postgis14(# geomfromtext('POINT(180 0)',4326),'SPHEROID["WGS
>> postgis14'# 84",6378137,298.257223563]');
>> st_distance_spheroid
>> ----------------------
>>    20037508.3427892
>
>
> On this request i got as result: 19903593.3909346
> on two systems:
>
> POSTGIS="2.0.0SVN" GEOS="3.2.0-CAPI-1.6.0" PROJ="Rel. 4.7.1, 23 September
> 2009" LIBXML="2.7.6"
> PosgreSQL 9.0.alpha 4
> Mac OS X 10.5.8
>
> POSTGIS="1.5.0SVN" GEOS="3.2.0-CAPI-1.6.0" PROJ="Rel. 4.6.1, 21 August 2008"
> LIBXML="2.7.3"
> PostgreSQL 8.3.7
> Linux Slackware 12.1
>
>
> --
> Olivier
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