GetMapTiles function

download map tiles from specified map tile servers such as openstreetmap or Google

Query the server for map tiles, defined uniquely by their X and Y ID and zoom. For offline usage, these map tiles are stored in a local directory Example OSM:http://a.tile.openstreetmap.org/10/549/335.png Also see https://wiki.openstreetmap.org/wiki/Tile_servers Example Google mobile: http://mt1.google.com/vt/lyrs=m&x=1325&y=3143&z=13 Example Google satellite: http://mt1.google.com/vt/lyrs=s&x=1325&y=3143&z=13

GetMapTiles(center = c(lat = 52.431635, lon = 13.194773), 
    lonR, latR, nTiles = c(3, 3), zoom = 13, type = c("google", 
        "google-m", "google-s", "osm", "osm-hot", "stamen-toner", 
        "stamen-terrain", "stamen-watercolor")[1], 
    urlBase = "http://mt1.google.com/vt/lyrs=m", tileDir = "/tmp/", 
    CheckExistingFiles = TRUE, TotalSleep = NULL, tileExt = ".png", 
    returnTiles = TRUE, verbose = 0)

Arguments

• center: optional center (lat first,lon second )
• lonR: longitude range
• latR: latitude range
• nTiles: number of tiles in x and y direction
• zoom: Google maps zoom level.
• type: choice of tile server
• urlBase: tileserver URL, alternatives would be "http://a.tile.openstreetmap.org/", "http://tile.stamen.com/toner/","http://tile.stamen.com/watercolor/"
• tileDir: map tiles can be stored in a local directory, e.g. "~/mapTiles/Google/"
• CheckExistingFiles: logical, if TRUE check if files already exist and only download if not!
• TotalSleep: overall time (in seconds) that one is willing to add in between downloads. This is intended to lower the risk of a server denial. If NULL no call to Sys.sleep is executed
• tileExt: image type of tile
• returnTiles: return tiles in a list?
• verbose: level of verbosity

Returns

list with important information

Author(s)

Markus Loecher

Note

Note that size is in order (lon, lat)

See Also

GetMap.bbox

Examples

if (0){
  
  #OSM, Ireland
  xlim = c(-7, -3.5) 
  ylim = c(51.35, 55.35)
  Dublin = c(lon=-6.266155,lat=53.350140)
  DublinMerc = geosphere_mercator(Dublin)
  
  ir.osm <- GetMapTiles(lonR=xlim, latR=ylim, zoom=7, verbose=1,
                        type = "osm", tileDir= TRUE)
  map = plotOSM(ir.osm)
  par("usr")#A vector of the form c(x1, x2, y1, y2)
  points(map$bbox$upperLeft,col=2,pch=20)
  points(map$bbox$lowerRight,col=2,pch=20)
  
  points(DublinMerc, col =2, pch=1,cex=1.5)
  
  ir.stamenToner <- GetMapTiles(lonR=xlim, latR=ylim, zoom=7,verbose=0,
                                type = "stamen", tileDir= TRUE)
  plotOSM(ir.stamenToner)
  
  ir.stamenWater <- GetMapTiles(lonR=xlim, latR=ylim, zoom=7, verbose=1,
                                type = "stamen-watercolor", tileDir= TRUE)
  plotOSM(ir.stamenWater)
 
  
  #############################################
  zoom=5
  nTiles = prod(NumTiles(lonR=c(-135,-66), latR=c(25,54) , zoom=zoom))
  us_google_5 = GetMapTiles(lonR=c(-135,-66), latR=c(25,54) , zoom=zoom, TotalSleep = 2*nTiles,
              type = "google", tileDir= TRUE, verbose = TRUE)
  
  PlotOnMapTiles(us_google_5)
  wtc_ll = getGeoCode("World Trade Center, NY")
  wtc_google_15=GetMapTiles(wtc_ll, zoom=15,nTiles = c(3,3), type = "google", 
                            tileDir= TRUE, verbose = 1)
  PlotOnMapTiles(wtc_google_15)
  wtc_google_16 =GetMapTiles(wtc_ll, zoom=16,nTiles = c(4,4), type = "google", 
                             tileDir= TRUE, verbose=1)
  PlotOnMapTiles(wtc_google_16)

  wtc_stamen=GetMapTiles(wtc_ll, zoom=15,nTiles = c(3,3), verbose=1,
                  type = "stamen-toner", tileDir= TRUE)
  PlotOnMapTiles(wtc_stamen)


###combine with leaflet:
#From:http://stackoverflow.com/questions/5050851/
#     best-lightweight-web-server-only-static-content-for-windows
#To use Python as a simple web server just change your working 
#directory to the folder with your static content and type 
#python -m SimpleHTTPServer 8000, everything in the directory
#will be available at http:/localhost:8000/
  
library(leaflet)
m = leaflet::leaflet() %>% 
  addTiles( urlTemplate = "http:/localhost:8000/mapTiles/OSM/{z}_{x}_{y}.png")
m = leaflet::leaflet() %>% 
  addTiles( urlTemplate = "http:/localhost:8000/mapTiles/Google/{z}_{x}_{y}.png")
m = m %>% leaflet::setView(-74.01312, 40.71180, zoom = 16)
m = m %>% leaflet::addMarkers(-74.01312, 40.71180)

#Quadriga:
m = m %>% leaflet::setView(13.39780, 52.51534, zoom = 16)
m = m %>% leaflet::addMarkers(13.39780, 52.51534)
}