Shape to DB, DB to SpatialPolygon
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):
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! Germ?n S?nchez german.sanchez at esade.edu El 08/04/2010, a las 13:17, Carson Farmer escribi?:
Hi Germ?n, 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, Germ?n S?nchez <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, Germ?n S?nchez german.sanchez at esade.edu
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-- Carson J. Q. Farmer ISSP Doctoral Fellow National Centre for Geocomputation National University of Ireland, Maynooth, http://www.carsonfarmer.com/