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> 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/lmkgmdoohpmhdcjg.png > > Thanks for any tip. --Mel. > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > 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
