R: Query the Open Street Map server for map tiles instead of...

GetOsmMap {RgoogleMaps} | R Documentation

## Query the Open Street Map server for map tiles instead of Google Maps

### Description

The querying parameters for Open Street Maps are somewhat different in this version. Instead of a zoom, center and size, the user supplies a scale parameter and a lat/lon bounding box. The scale determines the image size.

### Usage

    GetOsmMap(lonR = c(-74.02132, -73.98622), latR = c(40.69983,
        40.72595), scale = 20000, destfile = "MyTile.png", format = "png",
        RETURNIMAGE = TRUE, GRAYSCALE = FALSE, NEWMAP = TRUE, verbose = 1,
        ...)

### Arguments

`lonR` | longitude range
`latR` | latitude range
`scale` | Open Street map scale parameter. The larger this value, the smaller the resulting map tile in memory. There is a balance to be struck between the lat/lon bounding box and the scale parameter.
`destfile` | File to load the map image from or save to, depending on `NEWMAP`.
`format` | (optional) defines the format of the resulting image.
`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.
`verbose` | level of verbosity,
`...` | extra arguments to be used in future versions

### Value

map structure or URL used to download the tile.

### Note

The OSM maptile server is frequently too busy to accomodate every request, so patience is warranted.

### Author(s)

Markus Loecher

### Examples

    if (interactive()) {
     	CologneMap <- GetOsmMap(lonR= c(6.89, 7.09), latR = c(50.87, 51), scale = 150000,
                                destfile = "Cologne.png");
    	PlotOnStaticMap(CologneMap, mar=rep(4,4), NEWMAP = FALSE, TrueProj = FALSE, axes= TRUE);

    	PrincetonMap <- GetOsmMap(lonR= c(-74.67102, -74.63943), latR = c(40.33804,40.3556),
                                 scale = 12500, destfile = "Princeton.png");
    	png("PrincetonWithAxes.png", 1004, 732)
          PlotOnStaticMap(PrincetonMap, axes = TRUE, mar = rep(4,4));
        dev.off()
     }

[Package RgoogleMaps version 1.4.1 Index]