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copied!<p>Thanks for the carefully constructed question. It required just a couple of line changes to be able to use rworldmap (containing up-to-date countries) see below. I'm not an expert on CRS but I don't think the change I had to make to the proj4string makes any difference. Others might like to comment on that.</p> <p>This worked for me & gave :</p> <pre><code>> coords2country(points) [1] United Kingdom Belgium Germany Austria [5] Republic of Serbia </code></pre> <p>All the best, Andy</p> <pre><code>library(sp) library(rworldmap) # The single argument to this function, points, is a data.frame in which: # - column 1 contains the longitude in degrees # - column 2 contains the latitude in degrees coords2country = function(points) { countriesSP <- getMap(resolution='low') #countriesSP <- getMap(resolution='high') #you could use high res map from rworldxtra if you were concerned about detail # convert our list of points to a SpatialPoints object # pointsSP = SpatialPoints(points, proj4string=CRS(" +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0")) #setting CRS directly to that from rworldmap pointsSP = SpatialPoints(points, proj4string=CRS(proj4string(countriesSP))) # use 'over' to get indices of the Polygons object containing each point indices = over(pointsSP, countriesSP) # return the ADMIN names of each country indices$ADMIN #indices$ISO3 # returns the ISO3 code #indices$continent # returns the continent (6 continent model) #indices$REGION # returns the continent (7 continent model) } </code></pre>

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