Chris, Thanks, using `weights=TRUE` to compute the means fixed the problem. Perfect, --Mel.
On 10/18/2016 11:10 AM, chris english wrote: > > Mel, > > Looking at detail in cjg.png the northmost missing data island shows > approx 20-25 in Southern three quarters and 0-5 the small North at tip > of island. Directly above this 0-5 another coastal 0-5. > If a substantial east-west scarp bisected the island it might explain. > I would otherwise expect a very slight mismatch in projection, a thing > I often have problems with. > > Though reading raster::extract it looks like you want to employ the > weights are if your polys are relatively smaller than your cells. > > HTH > Chris > > > On Oct 18, 2016 4:35 PM, "Bacou, Melanie" <m...@mbacou.com > <mailto:m...@mbacou.com>> wrote: > > Hi, > I'm summarizing biophysical rasters (UDEL precipitation and > temperature) across administrative units for countries in Africa > using (pseudo code): > > raster::extract(udel, admin, fun=mean, na.rm=T, small=T) > > Out of the 756 units I need data for, extract() fails to return > means for a few coastal units (in red on the maps below) even > though the rasters show data at these locations. > > Is there a particular reason why this might happen? Shall I look > for possible geometry errors in my source shapefiles, or could > there be another reason? > > Maps here: > https://dl.dropboxusercontent.com/u/30925475/eclgcdmhapfplaml.png > <https://dl.dropboxusercontent.com/u/30925475/eclgcdmhapfplaml.png> > https://dl.dropboxusercontent.com/u/30925475/lmkgmdoohpmhdcjg.png > <https://dl.dropboxusercontent.com/u/30925475/lmkgmdoohpmhdcjg.png> > > Thanks for any tip. --Mel. > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org <mailto:R-sig-Geo@r-project.org> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > <https://stat.ethz.ch/mailman/listinfo/r-sig-geo> > [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
