Jaime, I've been successful in reading points from a PostGIS data base
through OGR; see
http://wiki.intamap.org/index.php/PostGIS
--
Edzer
Jaime Carrera wrote:
Hi list,
I've been looking around trying to solve this problem; unfortunately I
haven't found a way to solve it.
I have a database with sampling points with an associated sampling
date and would like to plot the density of sampling points on a
monthly basis for one year using spplot. However, I need to query the
database and import the result of the query into R to visualize the
data. I can import the query on a column-wise basis but the WKB data
are imported as chars into R (as expected). Is there a way by which I
could read these data (WKB geometry) once imported into R? Or is there
a way by which ReadOGR can read the outcome of the query?
I tried creating a temporary table through the query, but it seems
that ReadOGR can't read it.
Thanks for your help,
Jaime
As an example:
> db.execute("select geo.id as id,geo.wkb_geometry as geom from wells
as geo, gwhead as h where geo.id=h.id and
date_part('year',h.date)=2001 and h.gwhead<700",clear=F)
> ids<-db.read.column("id",as.is=F)
> geom<-db.read.column("geom",as.is=F)
Warning message:
In rpgsql.cast.values.default(data.col) :
Coercing PGSQL type 16437 to character
> geom
[1] "0101000020FF7F00000000000088FD2141000000C09BB95741"
[2] "0101000020FF7F00000000000088FD2141000000C09BB95741"
[3] "0101000020FF7F00000000000088FD2141000000C09BB95741"
[4] "0101000020FF7F00000000000088FD2141000000C09BB95741"
[5] "0101000020FF7F00000000000088FD2141000000C09BB95741"
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--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster,
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de/
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