Map census: rbind fortify spatial object in R with ggplot2

Question

I am trying to rbind the US and Canada census maps using ggplot2.

us <- readOGR(dsn = "00-raw/usmaps/us/", layer = "co99_d90")
canada <- readOGR(dsn = "00-raw/gcd_000b11a_e/", layer = "canada")

canada$id <- as.numeric(canada$id)
us$id <- as.numeric(us$id)

canada$id <- canada$id + length(unique(us$id))
na <- rbind(canada, us)

p <- ggplot() +
    geom_polygon(data = na, aes(x = long, y = lat, group = group, fill = pop),
                 color = "black", size = 0.25) +
    theme_nothing(legend = TRUE)

But there is some weird line.

The sources of the shapefiles are the following:

http://www12.statcan.gc.ca/census-recensement/2011/geo/bound-limit/files-fichiers/gcd_000b11a_e.zip

www2.census.gov/geo/tiger/PREVGENZ/co/co90shp/co99_d90_shp.zip

I really need those shapefiles since I want my borders to represent the counties for the US and the census division for Canada.

Answer 1

I made simplified versions of both shapefiles and put them into individual geojson files here.

You don't need to bind data to the fortified data frames if you use geom_map(). I have no idea if you need just ConUS or all US states & territories, so I split the diff and included Alaska. YMMV.

I simulated some data since we also don't have that from you.

library(rgdal)
library(rgeos)
library(maptools)
library(ggplot2)
library(ggthemes)
library(viridis)

canada <- readOGR("canada.geojson", "OGRGeoJSON", 
                  verbose=FALSE, stringsAsFactors=FALSE)
usa <- readOGR("usacounties.geojson", "OGRGeoJSON", 
               verbose=FALSE, stringsAsFactors=FALSE)

ca_map <- fortify(canada, region="CDUID")
us_map <- fortify(usa, region="CO99_D90_I")

set.seed(1492)
ca_pop <- data.frame(id=unique(canada$CDUID),
                     val=sample(100000, length(unique(canada$CDUID))),
                     stringsAsFactors=FALSE)
us_pop <- data.frame(id=unique(usa$CO99_D90_I),
                     val=sample(100000, length(unique(usa$CO99_D90_I))),
                     stringsAsFactors=FALSE)

gg <- ggplot()
gg <- gg + geom_map(data=ca_map, map=ca_map,
                    aes(long, lat, map_id=id),
                    size=0.1, fill=NA, color="#2b2b2b")
gg <- gg + geom_map(data=ca_pop, map=ca_map,
                    aes(fill=val, map_id=id))
gg <- gg + geom_map(data=us_map, map=us_map,
                    aes(long, lat, map_id=id),
                    size=0.1, fill=NA, color="#2b2b2b")
gg <- gg + geom_map(data=us_pop, map=us_map,
                    aes(fill=val, map_id=id))
gg <- gg + scale_fill_viridis(name="Population")
gg <- gg + coord_map(xlim=c(-170, -55), ylim=c(23.2, 80))
gg <- gg + theme_map()
gg

I'm 99% sure you're trying to show too much information but we don't really know what you're trying to do. If you are attempting to show population by US county and Canadian census id's then I'm 100% sure you're trying to show too much info.