On Wed, 12 May 2010, Tim Romel wrote:
Thanks you both for your quick responses.
Roger, could you please expand on how I would use ogr2ogr with R? I didn't
see any direct way to use ogr2ogr within R or to bring the results returned
by the ogr2ogr command into R spatial objects.
Through system(). Use ogr2ogr to write a temporary file for readOGR() to
pick up next. Then you can set the -sql or similar selection in the
ogr2ogr command.
Roger
Thanks again.
On Tue, May 11, 2010 at 6:21 AM, Roger Bivand <roger.biv...@nhh.no> wrote:
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.
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--
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
--
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
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