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rgdal: problem with grid data

3 messages · Agustin Lobo, Michael Sumner

Original
Agustin Lobo
# 
Hi!

  I read a grid file into R with
isrlc <- 
readGDAL("/media/Transcend/MASTER_ICTA2007_2008/GEODATA_miniprojs/Kefah/ISR_cov/isr_cov.gri")

While isrlc seems correct,  I'm getting an empty shapefile when I attempt to write:

writeOGR(isrlc,dsn="/media/Transcend/MASTER_ICTA2007_2008/GEODATA_miniprojs/Kefah", 
layer="ISR_cov2",driver="ESRI Shapefile")

Data from
http://www.diva-gis.org/data/cov/ISR_cov.zip

Thanks

Agus
Michael Sumner
# 
What are you expecting to get - a point for every raster cell?  If so,
use gridded(isrlc) <- FALSE to convert to a SPDF first - then the
write will work.

More complicated conversions are possible, such as with
as.SpatialPolygons.GridTopology.

Cheers, Mike.
On Tue, Mar 23, 2010 at 5:32 PM, Agustin Lobo <alobolistas at gmail.com> wrote:
Michael Sumner
# 
As a follow up, arguably writeOGR should either complain that it got a
raster, or perform the conversion to points automatically. I'm not
sure why writeOGR writes an empty shapefile in that case, but some
software cannot read them - so a warning at least would be helpful I
think. Roger?

Cheers, Mike.
On Tue, Mar 23, 2010 at 5:49 PM, Michael Sumner <mdsumner at gmail.com> wrote: