What's the use of converting ALL relations into geometries? Much of them have no relation to geometry - they are collections, routes and so on!!!
Kirill 2012/10/25 Paweł Paprota <[email protected]> > Hi Paul, > > I've been doing some similar work on aggregating way/node geometries and > there are some questions that need to be answered when considering > something like this: > > 1. What spatial type to store? OSM relations obviously can contain both > ways and nodes so when you do a simple ST_Union/ST_Collect you will get a > GEOMETRYCOLLECTION of LINESTRINGs and POINTs; GEOMETRYCOLLECTION is a bit > problematic as it is not supported by many PostGIS ST_* functions. > > What I've done myself is I convert node points into closed linestrings > with two points (X, X) thus when I aggregate node and way geometries I get > a MULTILINESTRING which is much more useful than GEOMETRYCOLLECTION. > > 2. What to do about hierarchical relations (that is, relations that have > other relations as members)? Should they be resolved down to nodes/ways? > > Paweł > > > On 10/25/2012 02:37 AM, Paul Norman wrote: > >> I keep a pgsnapshot database up to date on my home server for a local >> jxapi >> server and also for analysis. >> >> I have a linestring column built for the ways table, but there's no >> geometry >> for relations. >> >> I am wondering what would be involved with getting a geometry column built >> for the relations table. >> >> I expect this would slow down updates, but it would be invaluable to for >> analysis. >> >> I believe Ian Dees mentioned to me something about some work that had been >> done on this. >> >> Is there anything that I could do to help? I have minimal java knowledge >> and >> some postgis knowledge. >> >> >> ______________________________**_________________ >> osmosis-dev mailing list >> [email protected] >> http://lists.openstreetmap.**org/listinfo/osmosis-dev<http://lists.openstreetmap.org/listinfo/osmosis-dev> >> >> > > ______________________________**_________________ > osmosis-dev mailing list > [email protected] > http://lists.openstreetmap.**org/listinfo/osmosis-dev<http://lists.openstreetmap.org/listinfo/osmosis-dev> >
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