I run species distribution models in R and want to create variable rasters for the mainland of Africa, without the islands. I can only find shapefiles of Africa with its islands, not from the mainland only.
1) Where can I possibly download a shapefile of the mainland only?
2) If there is no shapefile, I would like to manually delete the islands from my raster. Is there a way to do this, f.e. setting parts of the rasters between certain coordinates to NA?
Yes, but you need to provide a minimal, self-contained, reproducible example. The easiest approach might be to use Africa polygons africa and do
library(raster)
afr <- aggregate(africa)
v <- disaggregate(afr)
a <- area(v)
afnois <- v[which.max(a), ]
And then used that in mask to remove the islands from the rasters
You can also create polygons with raster::drawPoly and use these for masking.
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