SOcool

[mdsumner]

Prototype:

library(sospatial)  ## devtools::install_github("AustralianAntarcticDivision/sospatial")
library(SOmap)
SOcool <- function(xs, ys, icedate = "2017-09-01") {
  ice <-  tibble::tibble(lon = rep_len(seq(-180, 179), length.out = length(packed_lats)), 
                lat = packed_lats/10,
                day = as.Date(rep(ice_dates, each = 360)))
  icedate <- as.Date(icedate)
  f <- "%Y-%m-%d"
  if (icedate < min(ice$day) || icedate > max(ice$day)) {
    stop(sprintf("sorry, available range of icedate is %s : %s", format(min(icedate), f), format(max(icedate), f)))
  }
                                                                
                                                                
  ind <- which(icedate == ice$day)
  x <- default_somap(xs, ys)
  ice <- dplyr::slice(ice, ind)
  ice[c("x", "y")] <- rgdal::project(as.matrix(ice[c("lon", "lat")]), projection(x$bathy))
  ix <- which(ice$x >= xmin(x$bathy) & ice$x <= xmax(x$bathy) &
                ice$y >= ymin(x$bathy) & ice$y <= ymax(x$bathy))
  ice <- dplyr::slice(ice, ix)
  lines(ice[c("x", "y")], lty = 2)
  x$ice <- ice
  invisible(x)
}

SOcool(xs, ys)

I expect sospatial will get incorporated into this package, though first we need a way to keep the ice data up to date - it's about a year out atm.