Map of disc golf popularity in Finland

disc_golf_in_Finland.R

library("ggplot2")
library("cowplot")
library("sp")
library("raster")
library("scales")
library("rgeos")

# course information, scraped from fgr.fi
fgr <- read.csv("fgr.csv")

# get map of finland and sub-regions
finland <- getData("GADM", country = "FIN", level = 3)
# combine few old subregions to get official 75 regions
finland <- gUnaryUnion(finland, finland$NAME_3)


# compute holes per sub-regreion 
x <- SpatialPointsDataFrame(coords = fgr[,1:2], data = data.frame(holes = fgr$holes),
  proj4string = CRS(as.character(finland@proj4string)))
holes_per_area <- unlist(over(finland, x, fn = sum))
names(holes_per_area) <- names(finland)
holes_per_area[is.na(holes_per_area)] <- 9 #Ilomantsi, actually has one course without address

# make new data for ggplot2
finland <- SpatialPolygonsDataFrame(finland,
  data = data.frame(id = names(finland), holes = holes_per_area))
dd <- fortify(finland)
dd <- cbind(dd, finland@data[dd$id,])

number_of_holes <- cut(fgr$holes, c(0,8,17,30))
levels(number_of_holes) <- c("less than 9", "9-17", "18 or more")

p <- ggplot(dd, aes(long, lat, group = group)) +
  geom_polygon(aes(fill = holes), colour = alpha("black", 1/2), size = 0.2) +
  scale_fill_gradientn(colours = rev(topo.colors(200)), name = "Number of holes in sub-region") +
  geom_point(data = fgr, aes(x = lon, y = lat, colour = number_of_holes, group = NULL),size = 3) +
  scale_colour_manual(values = alpha(c("white", "red", "black"), 0.9),
    name = "Number of holes on course") +
  theme(axis.ticks = element_blank(), axis.text = element_blank(),
    axis.title = element_blank(),
    panel.background = element_rect(fill = "white", colour = NA),
    panel.grid.minor = element_line(colour = NA),
    plot.title = element_text(face = "bold", size = 20),
    legend.background = element_rect(colour = 'grey', fill = 'grey', size = 5)) +
  ggtitle("Disc golf courses in Finland")

footnote <- paste0("Made with R using ggplot2, raster, rgeos, sp, scales, and cowplot packages.",
  "\nCourse information from http://www.fgr.fi\nSub-region boundaries from http://www.gadm.org\n",
  "https://en.wikipedia.org/wiki/Sub-regions_of_Finland")
ggdraw(add_sub(p, hjust = 0, x = 0, footnote))

fgr.csv