RgoogleMaps (version 1.4.2)

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, ...)

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

…

extra arguments to GetMap

Value

map tile

Examples

# NOT RUN {

 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") 








# }