Re: [mapserver-users] PostGIS layer projection
I expanded it even more with initial ogrinfo commands (great way to check extents, source projection, etc). Hope this helps the next person google-searching! Feel free to expand the wiki page with your own notes. -jeff On 2019-07-18 9:31 AM, Jeff McKenna wrote: I expanded the wiki page to include the output of psql's describe "\d" for that table. -jeff On 2019-07-18 8:37 AM, Jeff McKenna wrote: Hi Radim, Here is a working mapfile reprojecting a PostGIS layer: https://github.com/mapserver/mapserver/wiki/Reproject-PostGIS-Layer You ask good questions, that could likely just be tested by checking the postgres logs and executing the raw commands from those logs at the psql commandline and comparing. As you go down this path, please do add to that new wiki page with your own notes :) -jeff -- Jeff McKenna MapServer Consulting and Training Services https://gatewaygeomatics.com/ ___ mapserver-users mailing list mapserver-users@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] PostGIS layer projection
I expanded the wiki page to include the output of psql's describe "\d" for that table. -jeff On 2019-07-18 8:37 AM, Jeff McKenna wrote: Hi Radim, Here is a working mapfile reprojecting a PostGIS layer: https://github.com/mapserver/mapserver/wiki/Reproject-PostGIS-Layer You ask good questions, that could likely just be tested by checking the postgres logs and executing the raw commands from those logs at the psql commandline and comparing. As you go down this path, please do add to that new wiki page with your own notes :) -jeff -- Jeff McKenna MapServer Consulting and Training Services https://gatewaygeomatics.com/ ___ mapserver-users mailing list mapserver-users@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/mapserver-users
Re: [mapserver-users] PostGIS layer projection
Hi Radim, Here is a working mapfile reprojecting a PostGIS layer: https://github.com/mapserver/mapserver/wiki/Reproject-PostGIS-Layer You ask good questions, that could likely just be tested by checking the postgres logs and executing the raw commands from those logs at the psql commandline and comparing. As you go down this path, please do add to that new wiki page with your own notes :) -jeff -- Jeff McKenna MapServer Consulting and Training Services https://gatewaygeomatics.com/ On 2019-07-18 8:04 AM, Radim Blazek wrote: 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 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
Re: [mapserver-users] PostGIS layer projection
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 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
Re: [mapserver-users] PostGIS layer projection
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
