[postgis-users] Why unrecognized field type?

[Rémi Cura]

Or you can use pl-R to use R directly inside DB, which has some pros and
cons

Cheers,

Rémi-C


2013/12/3 Lee Hachadoorian <Lee.Hachadoorian+L at gmail.com>

> On Tue, Dec 3, 2013 at 11:50 AM, James David Smith <
> james.david.smith at gmail.com> wrote:
>
>> On 3 December 2013 15:55, Lee Hachadoorian <Lee.Hachadoorian+L at gmail.com>wrote:
>>
>>> On Tue, Dec 3, 2013 at 5:23 AM, James David Smith <
>>> james.david.smith at gmail.com> 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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