[R-sig-Geo] Dumping OGR database to dataframe(s)?

[Alex Mandel]

Jonathan Greenberg wrote:
> R-sig-geo'ers:
> 
>    I'm pushing forward with recoding starspan as a set of R functions so
> we can get the program back on track after a long hiatus with the
> development of a C version (I don't know C and don't have time to learn
> it, and we lost our master programmer who did know C), and I'm trying to
> decide if I should allow the vector side of the program to specifically
> require shapefiles, or to allow it to be more flexible and allow any
> type of ogr-readable file.  Here are a couple of questions:
> 
> 1) Is there a command to dump the database(s) of any ogr file to a
> dataframe, regardless of the data type?  Right now, all I have found is
> that I need to use the read.dbf() function in the shapefiles library for
> a shapefile-associated DBF.
> 2) Is there any way to figure out the particular driver (aka file type)
> of a file I'm trying to read with ogr without needing the layer name? 
> Alternatively, is there any way to list the layer names of an ogr file?
> 
>    Thanks -- I'm going to try to make a release of starspan in the next
> few weeks to have people try it out...
> 
> --j
> 

Jonathan,

1.If you read the ogr layer in with the Rgdal package then you can
easily extract the dataframe from the spatial object.

library(rgdal)
layer1 <-
readOGR("/home/madadh/ucd/geo290-sp09/client/data/joined.shp","joined")
dataframe1 <- layer1 at data

2. ogrInfo should have all the information you need you will need at
least the connection string/path to the source to use it though, aka DSN
according to ogr/gdal documentation. You'll just need to parse it's
output to grab the pieces for other commands.

Alex