Thanks, using `weights=TRUE` to compute the means fixed the problem.
On 10/18/2016 11:10 AM, chris english wrote:
> 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.
> On Oct 18, 2016 4:35 PM, "Bacou, Melanie" <m...@mbacou.com
> <mailto:m...@mbacou.com>> wrote:
> 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:
> Thanks for any tip. --Mel.
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