I have a census tiger line file for counties available from the Census website.
I am trying to display this file on a
fortify seems to jumble the regions. I can't find anyone else who has run into this error, but I'm certainly not doing anything out of the ordinary...
library(maptools) library(ggmap) library(rgeos) # read shapefile WGS84 <- CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0") Counties <- readShapeSpatial("tl_2013_us_county.shp", proj4string = WGS84) # limit to Ohio Counties <- Counties[ Counties$STATEFP == 39, ] # fortify Counties.fort <- fortify(Counties, region = "GEOID") # get base map and plot OhioMap <- get_map("Ohio", source = 'google', maptype = 'terrain', zoom=7) ggmap(OhioMap) + geom_polygon(aes(x=long, y=lat), fill = 'grey', alpha=0.4, color = 'black', data = Counties.fort)