README.md
In mdsumner/asosi: Get BOM Ice Imagery

asosi

Obtain Antarctic and Southern Ocean Sea Ice imagery from the BOM

This is a rough prototype and only some of the parameters are built in and generalized properly. Work in progress.

allow ability to put .gfw and .prj (or .vrt) next to original GIF
Allow control over which image (9D, 8D, 7D, etc.)
remove dependence on rgdal by hardcoding projected control points into package
build more visualization examples

Installation

Install with devtools.

devtools::install_github("mdsumner/asosi")

Examples

library(asosi)
library(rworldxtra)
data(countriesHigh)
library(rgdal)
ant <- subset(countriesHigh, SOVEREIGNT == "Antarctica")
library(graticule)
durv <- asosi(as.Date("2015-07-30"), region = "durville")
#> Warning in download.file(fname, tfile, mode = "wb"): cannot open: HTTP
#> status was '404 Not Found'
durvmap <- spTransform(ant, projection(durv))
durvgrat <- graticule(seq(135, 160, by = 5), seq(-70, -60, by = 2), proj = projection(durv))
plot(durv, addfun = function() {plot(durvmap, add = TRUE); plot(durvgrat, add = TRUE)}, maxpixels = ncell(durv))

#writeRaster(durv, gsub(".gif", ".tif", basename(durv)))

regions <- c(
    "casey", "davis", "durville", "mawson", "shackleton", "terranova",
    "westice", "ragnhild", "enderby", "capeadare", "sabrina"
  )
for (jj in seq_along(regions)) {
  simap <- asosi(region = regions[jj])
  elx <- extent(projectExtent(simap, "+proj=longlat +ellps=WGS84"))
  lon <- seq((xmin(elx) %/% 5) * 5, ((xmax(elx) %/% 5) + 1) * 5, by = 5)
  lat <- seq((ymin(elx) %/% 2) * 2, (ymax(elx) %/% 2 + 1) * 2, by = 2)
  ## put this in the function as a return property
  date <- as.Date(paste(format(Sys.Date(), "%Y"), substr(basename(filename(simap)), 10, 13)), "%Y %m%d")
  map <- spTransform(ant, projection(simap))
  grat <- graticule(lon, lat, proj = projection(simap), nverts = 80)
  plot(simap, addfun = function() {plot(map, add = TRUE); plot(grat, add = TRUE)}, maxpixels = ncell(simap))
  title(sprintf("%s %s", regions[jj], format(date)), line = -1.5, bg = "grey")
}