[postgis-users] Coordinate changes using transform from 1.3.1 to 1.3.6

[Mark Cave-Ayland]

Miguel R. Luaces wrote:

> Dear all,
> 
> we have a PostgreSQL 8.1 database with postgis 1.2 installed. We have 
> some data in the database stored using EPSG:23029.
> 
> We make a backup with pg_dump and we restore the database in PostgreSQL 
> 8.2 with Postgis 1.3.1 without any problem.
> 
> But, if we restore the backup in PostgreSQL 8.2 with Postgis 1.3.6, the 
> function transform() returns a different result. More precisely:
> 
> The same query:
> 
> select astext(the_geom), astext(transform(the_geom)) from monumentos 
> where id = ,
> 
> In Postgis 1.3.1:
> 
> "Castelo de San Antón";"POINT(549556.009066526 
> 4801796.3531214)";"POINT(-8.38839299999999 43.3657910268222)"
> 
> In Postgis 1.3.6:
> 
> "Castelo de San Antón";"POINT(549556.009066526 
> 4801796.3531214)";"POINT(-8.38839299999999 43.3666118995462)"
> 
> The second coordinate of the transformation to 4326 changes by 0.004 
> degrees (approx).
> 
> Any idea?
> 
> Thank you very much in advance.
> 
> Best regards,
>   Miguel


Hi Miguel,

What versions of PostgreSQL/PostGIS are you using on both servers, and 
with which versions of the PROJ.4 library?

SELECT version(), postgis_full_version();

Also can you confirm that the spatial_ref_sys entries for 23029 and 4326 
are identical between the two servers?


ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
http://www.siriusit.co.uk
t: +44 870 608 0063