[R-sig-Geo] Adding SQL "where" to readOGR

[Barry Rowlingson]

On Wed, Jul 3, 2013 at 10:46 AM, Roger Bivand <Roger.Bivand at nhh.no> wrote:

> It does vary from version to version, and may imply geometric where=,
> which may also drag GEOS into its build train.

 is that the build train for libgdal rather than for rgdal? Can
libgdal exist without GEOS?

> how much of the where=
> to parse in R before despatch.

 How about none of it. What does ogr2ogr do? It seems to just pass the
string through. I don't see why R would have to do anything with it
except check for errors if gdal returns a CPL_YOUR_SQL_MAKES_NO_SENSE
or CPL_YOU_TRIED_TO_DO_SOMETHING_THAT_NEEDS_GEOS_BUT_YOU_AINT_GOT_IT
error.

 I reckon attribute filtering would cover most of the 'can I do sql in
readOGR' messages I've seen.

> All welcome!

 One day...

Barry