[postgis-users] Workaround for "transform: couldn't project point" error?

[Mark Cave-Ayland]

On 18/11/11 03:19, Evan Martin wrote:

> I'm importing some data into a PostGIS DB. The points in the data come
> in various SRIDs, but I need to transform them all to 4326 to use the
> geography type.
>
> A simple ST_Transform() doesn't always work for this, because of the
> error in http://trac.osgeo.org/postgis/ticket/318 So I tried
> transforming via 3395, eg.
>
> SELECT
> ST_AsText(ST_Transform(ST_Transform(ST_GeomFromEWKT('SRID=4267;POINT(-31.94944
> 52.38833)'), 3395), 4326))
>
> This works for most points, but fails at the poles, eg.
>
> SELECT
> ST_AsText(ST_Transform(ST_Transform(ST_GeomFromEWKT('SRID=4267;POINT(-80
> -90)'), 3395), 4326))
> ERROR: transform: couldn't project point (-80 -90 0): tolerance
> condition error (-20)
>
> Is there any effective workaround for this? Is the bug likely to be
> fixed any time soon? It's been open for some time and a few people have
> run into it.

Hi Evan,

The "couldn't project point" message isn't being caused by PostGIS at 
all - PostGIS is simply passing back the error message from the PROJ.4 
library. Do you see the same error when using the proj executable to 
project the same point manually?


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

Sirius Labs: http://www.siriusit.co.uk/labs