On Sat, 8 May 2010, Brooks Kehler wrote:

Have a look at:

http://www.joeconway.com/plr/

http://www.bostongis.com/PrinterFriendly.aspx?content_name=postgresql_plr_tut01


That only gets you so far. Could Tim please try ogr2ogr with the -sql or -where or -spat arguments set to see whether these go in the correct direction, that is returning geometries meeting the given selection conditions? I have looked briefly at how hard it would be to add this functionality to readOGR(), but without a substantial re-write, it will not be easy. If there are other users who would value such an addition to readOGR, please indicate!

Roger



On Fri, May 7, 2010 at 5:35 PM, Tim Romel <tim.ro...@vistracks.com> wrote:

I have the need to bring spatial data into R from a postgres database.  I
am
trying to do this right now using rgdal with a command similar to the
following:

results=readOGR("PG:dbname='dbname' host='hostname' port='portnum'
user='username' password='pass' <password='p...@ssw0rd'>, layer="tablename")

This works in bringing back all data from the entire table.  However, this
is a very large table and I was wondering if there was a way to run a query
against the table instead of bringing back all data using readOGR.  I have
found no examples anywhere and have even seen suggestions that it is not
possible.  Is this the case?  If there are other libraries that support R's
SP library that allow access to postgres that would be great to know too.

Any help is much appreaciated.

Thanks.

       [[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo


        [[alternative HTML version deleted]]

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo


--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: roger.biv...@nhh.no

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo@stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Reply via email to