Last active
December 4, 2016 14:52
-
-
Save kzktmr/89049df857b1eff34e959416ea2146f4 to your computer and use it in GitHub Desktop.
Draw a very simple prefectural choropleth map of Japan with ggplot
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
ggJapanPrefecturesMap <- function (col = "white", fill = NULL, inset = TRUE, silent = FALSE, ...) | |
{ | |
require(Nippon) | |
if(require(ggplot2)){ | |
require(foreign) | |
m <- readShapePoly(system.file("shapes/jpn.shp", package = "Nippon")[1], | |
proj4string = CRS("+proj=longlat +datum=WGS84")) | |
if (inset) { | |
xy.okinawa <- m@polygons[[47]]@Polygons[[1]]@coords | |
xy.okinawa[, 1] <- xy.okinawa[, 1] + 7 | |
xy.okinawa[, 2] <- xy.okinawa[, 2] + 14 | |
m@polygons[[47]]@Polygons[[1]]@coords <- xy.okinawa | |
labpt <- m@polygons[[47]]@labpt | |
labpt[1] <- labpt[1] + 7 | |
labpt[2] <- labpt[2] + 14 | |
m@polygons[[47]]@labpt <- labpt | |
m@bbox[1, 1] <- 130 | |
m@bbox[2, 1] <- 31 | |
} | |
fm <- fortify(m) | |
fm$id <- as.numeric(fm$id) | |
d <- read.dbf(system.file("shapes/jpn.dbf", package="Nippon"), as.is=TRUE) | |
d$id <- as.numeric(d$SP_ID) - 1 | |
g <- ggplot(d) + theme_bw() | |
if(is.null(fill)){ | |
col <- head(rep(col, ceiling(47 / length(col))), 47) | |
g <- g + geom_map(map = fm, aes(map_id = id), fill = col, colour = "black", size = 0.2) | |
}else{ | |
g <- g + geom_map(map = fm, aes(map_id = id, fill = fill), colour = "black", size = 0.2) | |
} | |
g <- g + expand_limits(x = fm$long, y = fm$lat) + coord_map() + | |
theme(axis.title = element_blank()) | |
if (inset) { | |
g <- g + geom_line(data = data.frame(long = c(132, 135, 137, 137), lat = c(38, 38, 40, 43)), | |
mapping = aes(x = long, y = lat), colour = "black", size = 0.2) | |
} | |
if(!silent)plot(g) | |
coord <- as.data.frame(coordinates(m)) | |
colnames(coord) <- c("long", "lat") | |
return(invisible(list(plot = g, coordinates = coord))) | |
}else{ | |
return(JapanPrefecturesMap(col = col, inset = inset, ...)) | |
} | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment