Created
February 23, 2016 15:15
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Get total areas of spatialPolygonsDataFrame WGS84 objects
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| require(geosphere) | |
| get_areas = function(spdf){ | |
| polys = lapply(spdf@polygons, function(p) p@Polygons) | |
| sapply(polys, function(p){ | |
| coords = lapply(p, function(p) p@coords) | |
| ind_areas = lapply(coords, areaPolygon) | |
| sum(unlist(ind_areas)) | |
| }) | |
| } | |
| ## example | |
| # require(maptools) | |
| # data(wrld_simpl) | |
| # data.frame(id = wrld_simpl@data$NAME, | |
| # area = get_areas(wrld_simpl)/1e+06) |
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