[mapserver-users] PostGIS layer projection

[Jeff McKenna]

Hi Radim,

Give the Projection document a good read specifically the "Important 
Notes" section which I believe answers your questions: 
https://mapserver.org/mapfile/projection.html#important-notes

There are no specific driver rules; for something like a PostGIS 
connection you should be able to follow the "Important Notes" above. 
MapServer will assume that you have configured the driver properly (in 
the case of PostGIS, setting the SRID as well, since PostGIS requires 
that parameter to do a projection)

-jeff


-- 
Jeff McKenna
MapServer Consulting and Training Services
https://gatewaygeomatics.com/



On 2019-07-18 5:59 AM, Radim Blazek wrote:
> Hi,
> can you please explain how does re-projection of PostGIS layers work?
> If there is a POSTGIS layer with DATA without "using srid=" but
> PostGIS column has SRID defined, there is constraint for that SRID on
> the column and geometries have SRID set, is it necessary to define
> PROJECTION for that layer if SRID of the column is different from that
> of mapfile?
> 
> For example, geometry column has SRID=4326, geometries have SRID set, mapfile:
> 
> NAME test
>       PROJECTION
>           "init=epsg:3857"
>       END
>       LAYER test
>            CONNECTIONTYPE postgis
>            DATA "geo FROM test"
>       END
> END
> 
> if a request comes to render a map in 3857, will be geometries
> re-projected correctly from 4326 to 3857?
>