Paul,
I could just *kiss* you mate! :D
(Right now I'm feeling pretty ashamed for not thinking of it right away
... :] guess it's been too many hours coding... )
All the best,
Pedro.
On 11/23/2009 10:45 PM, Paul Ramsey wrote:
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.
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