On Tue, Dec 3, 2013 at 11:50 AM, James David Smith < [email protected]> wrote:
> On 3 December 2013 15:55, Lee Hachadoorian > <[email protected]>wrote: > >> On Tue, Dec 3, 2013 at 5:23 AM, James David Smith < >> [email protected]> wrote: >> >>> Hi all, >>> >>> Apologies for cross-posting this to the RPostrgeSQL and PostGIS mailing >>> lists, but I'm not sure where the problem lies. >>> >>> I am using the RPostgreSQL package of R to connect to my installation of >>> PostgreSQL/PostGIS. I want to retrieve some coordinates from my database >>> and run the below command. Is this just that R doesn't know what to do with >>> Geometry's, or is it something I should be more concerned about? I ask, as >>> I'm having some wider issues with my workflow and this may be related. >>> >>> Thanks >>> >>> James >>> >>> > dbGetQuery(con, "SELECT >>> > st_transform(st_setsrid(st_makepoint(soose::numeric, >>> > soosn::numeric),27700),4326) FROM stage WHERE ssid = '707187161010202'") >>> >>> st_transform >>> 1 0101000020E6100000F71184EF3961B3BF830420AF33C64940Warning message:In >>> postgresqlExecStatement(conn, statement, ...) : >>> RS-DBI driver warning: (unrecognized PostgreSQL field type geometry >>> (id:480912) in column 0) >>> >>> >>> >> James, >> >> R knows how to handle geometries using the sp package, but can't read the >> data in using RPostgreSQL. You would need to use readOGR() in the rgdal >> package. But what data do you actually need in R, and what do you intend to >> do with it? If you're not going to be mapping it or doing spatial >> statistics on it, there may be a way to get the data you want using >> RPostgreSQL. >> >> Best, >> --Lee >> > > Hi Lee, > > Thanks for the reply. I was really only after the x and y of the geom, so > I'm now using st_x and st_y functions to get that. I've also figured out > what was going on with my wider workflow (a typo!) , so now all is working > fine. It was good to understand how R deals with geom types though for > future reference. > > Cheers > > James > > That's what I suspected, so I was going to suggest what you've already figured out. BTW, R + PostGIS is an excellent toolchain, so if you do decide to push in that direction, Advanced Spatial Data Analysis with R by Bivand, et al. will be indespendible. http://www.asdar-book.org/ Best, --Lee
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