> [... deleting for the sake of brevity ...] > > >> This SQL variant does not return errors, but it isn't visible in my > >> QGIS > > project > >> (it's an ongoing project with about twenty layers built with PostGIS). > >> > >> Any advice? > >> > >> Should I direct this inquiry to the QGIS list? > >> > >> Thank you, > >> > >> Max > > It might be because it returns a geometry collection. I recall QGIS > > not liking geometry collections. > > Also depending on how you are creating this -- is this a view or an > > inline SQL, you might need to force the type for it to show as a layer option. > > Regina: In these subsequent queries you are specifying SRS 4326; shouldn't it > be 2163, the SRS of all of the other layers? > >
No. In subsequent queries, I used ST_Transform(geom,2163) only in the clustering to get a good cluster number and so we could use meters for our distance clustering. So 2163 was just used for input to ST_ClusterDBScan which returns a number. The geometry itself should still be in it's original 4326 srid unless you changed it. 4326 is still preferable for most visualization tools is preferable.