If it's just points, do it all on the server side, skip encoding formats select st_x(pt) as x, st_y(pt) as y from mytable where myclause();
P. On Mon, Nov 23, 2009 at 2:43 PM, Pedro Doria Meunier <[email protected]> wrote: > Thank you Paul and John for your ideas. :) > > Actually what I'm trying to do is to decode simple POINT geoms... > > This is what I've done in PHP (using the astext() approach) > > // extract the geometry > $geometry = str_replace("POINT(","", $loc); > $geometry = str_replace(")","",$geometry); > $coordinate = explode(" ",$geometry); > $lon=$coordinate[0]; > $lat=$coordinate[1]; > > Now this was for the web interface... ( the user can wait another 100ms or > so ... :] ) > As far as a server solution is concerned this *is* a time-consuming > procedure... especially so when you've got *thousands* of connections per > minute... > > Furthermore, I'm developing the "beast" in Qt4 and - *ahem* - had never > needed to use libpq so I'm a bit lost here... :) > > Could someone be so kind as to point to a code example (outside using > astext() method) ? :] > > P.S. @John - found this to be interesting as I could store it in QByteArray > and go from there... ;) -- the real question here is: how to interpret the > byte array? > > BR, > Pedro. > > > On 11/23/2009 09:50 PM, Paul Ramsey wrote: >> >> That depends entirely on what you're planning to do with them once you >> get them. You'll probably want to serialize them into a known form so >> you can use them on the client side. ST_AsText() is one, very heavy, >> option. Mapserver, to take an example, uses >> encode(ST_AsBinary(ST_Force2D(geom)), 'hex'), so what goes over the >> wire is hex strings, but those are easy to turn into binary arrays, in >> WKB format, suitable for reading by a number of C++ libraries (like >> OGR or GEOG or etc). >> >> Best, >> >> P. >> >> On Mon, Nov 23, 2009 at 1:19 PM, Pedro Doria Meunier >> <[email protected]> wrote: >> >>> >>> Hi All, >>> >>> First off sorry for cross-posting. I'm hoping for a bigger audience... :] >>> >>> As for my question: >>> >>> How does one deal with Postgis geom fields in C++ ? >>> Google hasn't offered much help so far. >>> >>> I know I can make a "SELECT astext(my_geom) FROM my_table" and after >>> parsing >>> the resulting text. >>> This seems a bit awkward and time-consuming... >>> >>> Is there a better way to deal with it? >>> >>> Already thankful for any ideas, >>> BR, >>> Pedro. >>> _______________________________________________ >>> postgis-users mailing list >>> [email protected] >>> http://postgis.refractions.net/mailman/listinfo/postgis-users >>> >>> >> >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
