R/SpatialToPBS.R

In iNZightVIT/RgoogleMaps: Overlays on Google map tiles in R

SpatialToPBS <- structure(function#converts spatial objects as defined in package sp to simpler PBSmapping type dataframes 
### The PlotPolysOnStaticMap() function currently does not take sp objects directly but instead needs
### PBSmapping type data.frames. This function converts sp objects into such.                         
(
  xy, ##<< spatial object, such as SpatialPoints, SpatialPolygons, etc..
  verbose=0 ##<< level of verbosity
  ) {
  fun = points
  if (inherits(xy, 'Spatial')) {
    b = sp::bbox(xy)
    if (inherits(xy, 'SpatialPoints')) {
      xy = sp::coordinates(xy)
    } else if (inherits(xy, 'SpatialPolygons')) {
      x = unlist(lapply(xy@polygons, function(i)slot(i, 'Polygons')))
      x = lapply(x, function(x)slot(x, 'coords'))
      xy = matrix(ncol=4, nrow=0, dimnames=list(NULL, c("PID","POS","X", "Y")))
      for (i in 1:length(x)) {
        n = nrow(x[[i]])
        xy = rbind(xy, cbind(PID=rep(i,n),POS=1:n,x[[i]]))
      }
      fun = lines
      #colnames(xy) = c("X", "Y")
      attr(xy, "projection" ) <- "LL"
    }
  } else {
    b = rbind(range(xy[,1], na.rm=TRUE), range(xy[,2], na.rm=TRUE))
  }
  
  return(list(xy=xy, bb=b, fun=fun))
### list with elements xy = converted object, bb = bounding box, fun = plot function
}, ex = function(){
  if (interactive()) {
  data("NYleukemia", envir = environment())
  population <- NYleukemia$data$population
  cases <- NYleukemia$data$cases
  mapNY <- GetMap(center=c(lat=42.67456,lon=-76.00365), 
                  destfile = file.path(tempdir(),"NYstate.png"), 
                  maptype = "mobile", zoom=9)
  #mapNY=ReadMapTile("NYstate.png")
  clrStuff=ColorMap(100*cases/population, alpha = 0.35, log = TRUE)
  NYpolys = SpatialToPBS(NYleukemia$spatial.polygon)
  PlotPolysOnStaticMap(mapNY, NYpolys$xy, col = clrStuff$colcode, add = FALSE)
  legend("topleft", legend = clrStuff$legend, fill = clrStuff$fill, 
         bg = rgb(0.1,0.1,0.1,0.3))
}
  
})