[R-sig-Geo] Shape to DB, DB to SpatialPolygon

[Roger Bivand]

On Mon, 12 Apr 2010, Germán Sánchez Hernández wrote:

> Hi Carson (and list!),
>
> I have corretly installed rgdal package in R (with some initial problems 
> but finally working).
>
> If I run ogrDrivers() no driver for PostgreSQL is listed (remember that 
> the postgresql database is correctly running with the PostGIS extension, 
> and I can connect through RODBC package):

The OGR driver will only be present if you have built OGR with PostGIS 
enabled. If you use the CRAN Windows 32-bit binary, or the CRAN extras OSX 
32-bit or Windows 64-bit binaries, the driver is not included. To use 
PostGIS with OGR, install GDAL with PostGIS enabled, and check with:

$ ogrinfo --formats

Until you see PostGIS/PostgreSQL there, you will not see it inside R 
either, having installed rgdal from source. Using PostGIS effectively 
presupposes that you have some experience in installing software from 
source, and that your platform has the necessary build trains; these kinds 
of things rarely work "out of the box". The rgdal package as a binary has 
most commonly used drivers, and more will not be added, because they 
depend on libraries/DLLs external to GDAL/OGR.

Roger

>
>> ogrDrivers()
>             name write
> 1          AVCBin FALSE
> 2          AVCE00 FALSE
> 3             BNA  TRUE
> 4             CSV  TRUE
> 5             DGN  TRUE
> 6             DXF  TRUE
> 7  ESRI Shapefile  TRUE
> 8      Geoconcept  TRUE
> 9         GeoJSON  TRUE
> 10         GeoRSS  TRUE
> 11            GML  TRUE
> 12            GMT  TRUE
> 13  GPSTrackMaker  TRUE
> 14            GPX  TRUE
> 15            KML  TRUE
> 16   MapInfo File  TRUE
> 17         Memory  TRUE
> 18         PCIDSK FALSE
> 19            REC FALSE
> 20            S57  TRUE
> 21           SDTS FALSE
> 22         SQLite  TRUE
> 23          TIGER  TRUE
> 24        UK .NTF FALSE
> 25            VFK FALSE
> 26            VRT FALSE
> 27         XPlane FALSE
>
> What am I missing?
>
> Thank you!
> Germán Sánchez
> german.sanchez at esade.edu
>
> El 08/04/2010, a las 13:17, Carson Farmer escribió:
>
>> Hi Germán,
>>
>> Have a look at package rgdal and the readOGR function.
>>
>>> library(rgdal)
>>> ?readOGR
>>
>> Here is a link with a quick bit on using rgdal to access a postgis table:
>> http://wiki.intamap.org/index.php/PostGIS
>>
>> Regards,
>>
>> Carson
>>
>> On Thu, Apr 8, 2010 at 11:21 AM, Germán Sánchez
>> <german.sanchez at ais-int.com> wrote:
>>> Dear all,
>>>
>>> I've working with spatial data since only a few months. I know how to
>>> handle this kind of data in R using the sp package. I know how to load
>>> shapes, plot them, merge their polygons, plotting labels, etc.
>>>
>>> I have installed a postgis database and I can connect to it from R via
>>> RODBC without problems. I can load a shape file (.shp and so) into the
>>> database (command shp2pgsql  to create the needed .sql). It creates a
>>> table with some usual fields (area, perimeter, district, etc) and the
>>> special one: the_geom.
>>>
>>> Now, I want to load this data to a SpatialPolygon (or
>>> SpatialPolygonDataFrame) object using the RODBC driver. I would like to
>>> get the same object as if I have used the "readShapePoly" function from sp
>>> package directly over the .shp file.
>>>
>>> Any idea? Is there a direct solution or I have to build the polygon myself?
>>>
>>> Thank you,
>>> Germán Sánchez
>>> german.sanchez at esade.edu
>>>
>>> _______________________________________________
>>> R-sig-Geo mailing list
>>> R-sig-Geo at stat.math.ethz.ch
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>
>>
>>
>> --
>> Carson J. Q. Farmer
>> ISSP Doctoral Fellow
>> National Centre for Geocomputation
>> National University of Ireland, Maynooth,
>> http://www.carsonfarmer.com/
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at 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.Bivand at nhh.no