{"id":3679,"date":"2015-09-19T14:34:10","date_gmt":"2015-09-19T19:34:10","guid":{"rendered":"http:\/\/rud.is\/b\/?p=3679"},"modified":"2018-03-10T08:01:38","modified_gmt":"2018-03-10T13:01:38","slug":"a-package-full-o-pirates-makin-interactive-pirate-maps-in-arrrrrrstats","status":"publish","type":"post","link":"https:\/\/rud.is\/b\/2015\/09\/19\/a-package-full-o-pirates-makin-interactive-pirate-maps-in-arrrrrrstats\/","title":{"rendered":"A Package Full o’ Pirates & Makin’ Interactive Pirate Maps in arrrrrRstats"},"content":{"rendered":"

Avast, me hearties! It’s time four t’ annual International Talk Like a Pirate Day #rstats<\/code> post!<\/p>\n

(OK, I won’t make you suffer continuous pirate-speak for the entire post)<\/p>\n

I tried to be a bit more practical this year and have two treasuRe chests for you to (hopefully) enjoy.<\/p>\n

A Package Full o’ Pirates<\/h3>\n

I’ve covered the Anti-shipping Activity Messages (ASAM) Database before<\/a> for TLAPD before but getting, updating and working with the data has more pain points than it should, so I wrapped a small package<\/a> around it.<\/p>\n

Here’s how to get all pirate<\/em> attacks this year (2015) so far:<\/p>\n

# devtools::install_github(\"hrbrmstr\/asam\")\nlibrary(asam)\n\ndata(asam_shp)\npirates <- subset(asam_shp,\n                  grepl(\"pirate\", Aggressor, ignore.case=TRUE) &\n                  format(DateOfOcc, \"%Y\") == \"2015\")\n\nnrow(pirates)\n## [1] 78<\/pre>\n
It looks like there have been 78 registered pirate attacks this year. The National Geospatial Intelligence Agency (NGIA) marks the attacks by lat\/lon and<\/em> also by region\/subregion, and I managed to obtain the official polygons for these regions, so we can plot these attacks on a world map and also show the subregions:<\/p>\n
library(ggplot2)\n\n# get the ASAM subregion polygons\nsubregions <- asam_subregions()\nsubregions_map <- fortify(subregions)\n\n# get the world map\nworld <- map_data(\"world\")\n\n# get the points for the pirate attack occurrences\npirate_pts <- data.frame(pirates)\n\ngg <- ggplot()\n\n# world map layer\ngg <- gg + geom_map(data=world, map=world,\n                    aes(x=long, y=lat, map_id=region),\n                    color=\"black\", fill=\"#e7e7e7\", size=0.15)\n# ASAM regions layer\ngg <- gg + geom_map(data=subregions_map, map=subregions_map,\n                    aes(x=long, y=lat, map_id=id),\n                    color=\"white\", fill=\"white\", size=0.15, alpha=0)\n\n# attacks\ngg <- gg + geom_point(data=pirate_pts, color=\"black\", fill=\"yellow\", \n                      aes(x=coords.x1, y=coords.x2), shape=21)\n\ngg <- gg + xlim(-170, 170)\ngg <- gg + ylim(-58, 75)\ngg <- gg + coord_map(\"mollweide\")\ngg <- gg + theme_map()\ngg <- gg + theme(panel.background=element_rect(fill=\"steelblue\"))\ngg<\/pre>\n
\"README-map-1\"<\/p>\n
There is quite a bit more data than just location, though and we can work with it much<\/em> better in an interactive map.<\/p>\n
Makin' Interactive Pirate Maps<\/h3>\n
Now, what makes the following an interactive pirate<\/em> map is not so much the fact that we'll be plotting points of pirate attacks on a Leaflet map, but<\/em> we'll also be using a pirate treasure map theme<\/em> on the Leaflet map.<\/p>\n
Let's start with showing how to use a general pirate map theme before adding in the ASAM data.<\/p>\n
You'll have to pause here and head on over to MapBox<\/a> to register for a (free) account. You'll need to go through the gyrations<\/a> to eventually get a public token and mapbox id to use the pirate map tiles they have. I store those in my .Renviron<\/code> so I don't have to cut\/paste inane strings when I need to use this, or other, APIs or need to keep them from prying eyes. Since MapBox exposes these strings in GET<\/code> call URLs, the use of environment variables is strictly for convenience in this case.<\/p>\n
library(leaflet)\n\nmapbox_public_token <- Sys.getenv(\"MAPBOX_PUBLIC_TOKEN\")\nmapbox_map_id <- Sys.getenv(\"PIRATE_MAP_ID\")\nmapbox_url <- \"https:\/\/a.tiles.mapbox.com\/v4\/%s\/{z}\/{x}\/{y}.png?access_token=%s\"\nmapbox_tiles_template <- sprintf(mapbox_url, mapbox_map_id, mapbox_public_token)<\/pre>\n
Now, what good is a pirate map without an 'X' marking the spot for some treasure. For that we'll need an 'X':<\/p>\n
\"\"<\/p>\n
in a format we can use with Leaflet:<\/p>\n
x_marker <- icons(\"http:\/\/rud.is\/dl\/x.png\",\n                  iconHeight=64, iconWidth=64,\n                  iconAnchorX=32, iconAnchorY=32)<\/pre>\n
Now, we can display a pirate map for all scurvy dogs to see:<\/p>\n
leaflet() %>%\n  addTiles(mapbox_tiles_template) %>%\n  setView(lng=-50.9249, lat=45.68929, zoom=3) %>%\n  addMarkers(-70.2667, 43.6667, icon=x_marker)<\/pre>\n
<\/p>\n