[postgis-users] Inserting New SRID into spatial_ref_sys Table

[Pierre Racine]

> No, the rasters in the srtm3 table are in SRID 4326.
> 
> I want to retrieve the altitude value in SRID 4978.

If you mean your point (ST_Point(126.5,37.5)) is in SRID 4978 then the transformation part of the query is inverted. Should be:

select ST_Value(rast, ST_Transform(ST_SetSRID(ST_Point(126.5,37.5),
4978), 4326)) from srtm3 where filename='N37E126.hgt';

> > Just to double check:
> >
> > -rasters in the srtm3 table are also in the SRID 4978?
> >
> > -What if you do:
> >
> > SELECT ST_X(ST_Transform(ST_SetSRID(ST_Point(126.5,37.5), 4326),
> > 4978))), ST_Y(ST_Transform(ST_SetSRID(ST_Point(126.5,37.5), 4326),
> > 4978)))
> >
> > -It might also be that the point actually does not intersects with the
> > image. What if you add
> >
> > WHERE ST_Intersects(rast,
> > ST_Transform(ST_SetSRID(ST_Point(126.5,37.5),
> > 4326), 4978)))
> >
> > To your query?
> >
> > Pierre