PlotOnStaticMap {RgoogleMaps}

overlays plot on background image of map tile

Description

This function is the workhorse of the package RgoogleMaps. It overlays plot on background image of map tile

Usage

PlotOnStaticMap(MyMap, lat, lon, destfile, zoom = NULL, 


    size, GRAYSCALE = FALSE, add = FALSE, FUN = points, 


    mar = c(0, 0, 0, 0), NEWMAP = TRUE, TrueProj = TRUE, 


    axes = FALSE, atX = NULL, atY = NULL, verbose = 0, 


    ...)

Arguments

MyMap

optional map object

lat

latitude values to be overlaid

lon

longitude values to be overlaid

destfile

File to load the map image from or save to, depending on whether MyMap was passed.

zoom

Google maps zoom level. optional if MyMap is passed, required if not.

size

desired size of the map tile image. defaults to maximum size returned by the Gogle server, which is 640x640 pixels

GRAYSCALE

Boolean toggle; if TRUE the colored map tile is rendered into a black & white image, see RGB2GRAY

add

start a new plot or add to an existing

FUN

plotting function to use for overlay; typical choices would be points and lines

mar

outer margin in plot; if you want to see axes, change the default

NEWMAP

load map from file or get it "new" from the static map server

TrueProj

set to FALSE if you are willing to accept some degree of inaccuracy in the mapping. In that case, the coordinates of the image are in lat/lon and the user can simply overly points/lines/axis without worrying about projections

axes

overlay axes ?

atX

numeric; position of ticks on x-axis; if missing, axTicks is called for nice values; see axis

atY

numeric; position of ticks on y-axis; if missing, axTicks is called for nice values; see axis

verbose

level of verbosity

...

further arguments to be passed to FUN

Value

the map object is returned via invisible(MyMap)

Author(s)

Markus Loecher

Examples

#The first step naturally will be to download a static map from the Google server. A simple example:





  if (0){


    lat = c(40.702147,40.711614,40.718217);


    lon = c(-74.015794,-74.012318,-73.998284);


    center = c(mean(lat), mean(lon));


    zoom <- min(MaxZoom(range(lat), range(lon)));


    #this overhead is taken care of implicitly by GetMap.bbox();              


    MyMap <- GetMap(center=center, zoom=zoom,markers = paste0("&markers=color:blue|label:S|",


             "40.702147,-74.015794&markers=color:green|label:G|40.711614,-74.012318&markers=",


             "color:red|color:red|label:C|40.718217,-73.998284"), destfile = "MyTile1.png");


                   


     tmp <- PlotOnStaticMap(MyMap, lat = lat, 


                            lon = lon, 


                            destfile = "MyTile1.png", cex=1.5,pch=20,


                            col=c('red', 'blue', 'green'), add=FALSE);


     #and add lines:


     PlotOnStaticMap(MyMap, lat = c(40.702147,40.711614,40.718217), 


                     lon = c(-74.015794,-74.012318,-73.998284), 


                     lwd=1.5,col=c('red', 'blue', 'green'), FUN = lines, add=TRUE)


     	


  }