On 27 April 2012 00:05, Alvaro Tejero Cantero <alv...@minin.es> wrote: > Hi Mike! > > Thank you. Your tip about loading numpy data into PostgreSQL will be key for > my application > (http://stackoverflow.com/questions/8144002/use-binary-copy-table-from-with-psycopg2)
Great it's helpful! It probably deserves a better publishing platform than SO though. > In fact, do you know about the reverse process (loading to numpy arrays)? It > seems that Psycopg2 cannot do it but there is a project tackling that > problem --- I don't know if this could eventually be incorporated into the > mainstream driver (http://code.google.com/p/pgnumpy/ ). I've never heard of the package until now, but I'll check it out. There appears to be a sizable niche of presumably scientists that require linkage beteen numpy and postgres. (snip) > > That is what I was hoping for (only with less overhead from the 2nd, unused > coordinate). Is it is possible to build the LINESTRING from the interval > type on the fly for these operations (so as to keep the in-disk > representation compact and also supportive of the exclude constraint)? I think you mean using an aggregate to combine many intervals from several rows into one. I don't see any aggregate functions for the range type, and as I mentioned, it wouldn't know how to express the union of two ranges that don't touch (i.e., a discontinuous range, which would require some MULTI* structure). PostGIS has several aggregates, like ST_Union and ST_MemUnion, all are pretty reliable and fast. Not sure about the exclude constraint, but I think it is based on the GiST index. -Mike _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users