[postgis-devel] [PostGIS] #318: 900913->4326 Transform
PostGIS
trac at osgeo.org
Wed Nov 25 10:17:02 PST 2009
#318: 900913->4326 Transform
---------------------+------------------------------------------------------
Reporter: pramsey | Owner: mcayland
Type: defect | Status: new
Priority: medium | Milestone: PostGIS 1.5.0
Component: postgis | Version: trunk
Keywords: |
---------------------+------------------------------------------------------
Originally reported on postgis-users against 1.3.6, strange results are
also available on 1.5:
{{{
geog=# select postgis_full_version();
postgis_full_version
----------------------------------------------------------------------------------------------------------------------------
POSTGIS="1.5.0SVN" GEOS="3.2.0-CAPI-1.6.0" PROJ="Rel. 4.6.1, 21 August
2008" USE_STATS (procs from 1.5 r4836 need upgrade)
(1 row)
geog=# SELECT
ASTEXT(ST_Transform(ST_SetSRID(ST_Point(-633510.090428,7506727.67383),900913),4326));
astext
-------------------------------------------
POINT(-5.69091796875412 55.7394816986905)
(1 row)
geog=# SELECT
ASTEXT(ST_Transform(ST_SetSRID(ST_Point(-305748.113141,7834489.65112),900913),4326));
ERROR: transform: couldn't project point (-305748 7.83449e+06 0): failed
to load NAD27-83 correction file (-38)
HINT: PostGIS was unable to transform the point because either no grid
shift files were found, or the point does not lie within the range for
which the grid shift is defined. Refer to the ST_Transform() section of
the PostGIS manual for details on how to configure PostGIS to alter this
behaviour.
geog=# SELECT
ASTEXT(ST_Transform(ST_SetSRID(ST_Point(-305748.113141,7834489.65112),900913),4269));
astext
-------------------------------------------
POINT(-2.74658203125265 57.3620898624176)
(1 row)
geog=# SELECT
ASTEXT(ST_Transform(ST_SetSRID(ST_Point(-305748.113141,7834489.65112),900913),4267));
astext
-------------------------------------------
POINT(-2.74658203125265 57.3620898615614)
(1 row)
}}}
Note that for some reason we get NAD27/83 grid failure in the 900913->4326
case but *not* in the transforms into NAD83 and NAD27!
--
Ticket URL: <http://trac.osgeo.org/postgis/ticket/318>
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