Hi Jeff, thanks, yes I have read that. But I also read that "using srid= is optional but improves performance" so there was a little chance that re-projection could be done anyway if a different SRID is found on geometry.
If there is no further transformation, what difference "using srid=" does? What happens if SRID is not set on column and there are mixed geoms' SRIDs. I mean, where is CRS transformation done if request CRS != layer CRS != column CRS? I would expect calling directly PostGIS ST_Transform(geom, request_srid), which would by pass LAYER.PROJECTION. Radim On Thu, Jul 18, 2019 at 12:31 PM Jeff McKenna <jmcke...@gatewaygeomatics.com> wrote: > > 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? > > > _______________________________________________ > mapserver-users mailing list > mapserver-users@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/mapserver-users _______________________________________________ mapserver-users mailing list mapserver-users@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/mapserver-users