Hi,
If you have your data loaded into R as spatial objects, you can find in
which polygons the points fall using the overlay() function from the
sp-pacakge. See the documentation there. I'm not sure what to do if the
point falls outside a polygon and you need the nearest.
cheers,
Paul
brwin...@aol.com schreef:
Greetings
I have a large number of long-lat locations dispersed over the US and need
to identify which US county that each point is located in (or nearest to).
After reading the past posts and Roger's book, I have been able to use the
overlay function
to identify the appropriate counties for the set of locations
with long-lats lying within or on a polygon boundary. However, due to
longlat precision errors (I am assuming), some of the points lie outside
all of
my shapefile's county polygon boundaries.
Is there an R function similar to "overlay" that I could use to find which
county polygon is closest to each of my longlat points that do not lie
within the shapefile's polygons? I have spent quite a bit of time
searching
and browsing past list discussions and can seem to find my answer.
My apologies if I have missed an obvious answer.
Joe
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