RgoogleMaps: GetMap.bbox – R documentation

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GetMap.bbox

GetMap bbox

Description

Wrapper function for GetMap. Query the Google server for a static map tile, defined primarily by its lat/lon range and/or center and/or zoom.

Multiple additional arguments allow the user to customize the map tile.

Usage

GetMap.bbox(lonR, latR, center, size = c(640, 640), 


    destfile = "MyTile.png", MINIMUMSIZE = FALSE, RETURNIMAGE = TRUE, 


    GRAYSCALE = FALSE, NEWMAP = TRUE, zoom, verbose = 0, 


    SCALE = 1, 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/", ...)

Arguments

`lonR`	longitude range
`latR`	latitude range
`center`	optional center
`size`	desired size of the map tile image. defaults to maximum size returned by the Gogle server, which is 640x640 pixels
`destfile`	File to load the map image from or save to, depending on `NEWMAP`.
`MINIMUMSIZE`	reduce the size of the map to its minimum size that still fits the lat/lon ranges ?
`RETURNIMAGE`	return image yes/no default: TRUE
`GRAYSCALE`	Boolean toggle; if TRUE the colored map tile is rendered into a black & white image, see RGB2GRAY
`NEWMAP`	if TRUE, query the Google server and save to `destfile`, if FALSE load from destfile.
`zoom`	Google maps zoom level. optional
`verbose`	level of verbosity
`SCALE`	use the API's scale parameter to return higher-resolution map images. The scale value is multiplied with the size to determine the actual output size of the image in pixels, without changing the coverage area of the map
`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/"
`...`	extra arguments to GetMap

Value

map tile

Author(s)

Markus Loecher

Examples

if (0){


 	mymarkers <- cbind.data.frame(lat = c(38.898648,38.889112, 38.880940), 


          lon = c(-77.037692, -77.050273, -77.03660), size =  c('tiny','tiny','tiny'), 


          col = c('blue', 'green', 'red'), char = c('','',''));





	##get the bounding box:


  	bb <- qbbox(lat = mymarkers[,"lat"], lon = mymarkers[,"lon"]);


  


	##download the map:


  	MyMap <- GetMap.bbox(bb$lonR, bb$latR, destfile = "DC.png", GRAYSCALE =TRUE,


                markers = mymarkers);


 	##The function qbbox() basically computes a bounding box for the given lat,lon 


   #points with a few additional options such as quantile boxes, additional buffers, etc.  


  	bb <- qbbox(c(40.702147,40.711614,40.718217),c(-74.015794,-74.012318,-73.998284), 


            TYPE = "all", margin = list(m=rep(5,4), TYPE = c("perc", "abs")[1]));


 	##download the map:           


	MyMap <- GetMap.bbox(bb$lonR, bb$latR,destfile = "MyTile3.png", maptype = "satellite") 





}

RgoogleMaps

Overlays on Static Maps

v1.4.5.3

GPL

Authors