[R-sig-Geo] ogr2ogr for converting postGIS layer to shapefile

[Murray Richardson]

Hello list members,

I think I must be missing some obvious documentation somewhere; I'm not 
sure how I can access ogr2ogr vial R to convert a postGIS layer to a 
shapefile.  Must I use readOGR and writeOGR in rgdal instead or is there 
a way to call ogr2ogr directly? If so do I have to call the ogr2ogr 
binaries from FWTools?

On a more or less related topic - is it possible to convert a  
SpatialLines class to a  polygon feature class and  specify a threshold 
distance withing which line features will be treated as equivalent (i.e. 
to reduce spurious polygons at polygon boundaries).  Or even better 
could ogr be used to do this directly on a postGIS layer?  I know this 
is moving out of R territory but if anyone knows off hand I would 
appreciate your help.

Also - where do I search the complete r-sig-geo archives rather than 
have to do it one month at a time?

Thanks,

Murray