places tiles on plot
plotOSM(mt, upperLeft, lowerRight, lat, lon, add = FALSE,
removeMargin = TRUE, verbose = 0, ...)
returns map object invisibly
list returned by GetMapTiles
upperLeft corner in lat/lon of the plot region
lowerRight corner in lat/lon of the plot region
latitude values to be overlaid, if any
longitude values to be overlaid, if any
level of verbosity
further arguments to be passed to rasterImage
Markus Loecher