R: Add a Scalebar to a Map

mapScalebar {oce} | R Documentation

## Add a Scalebar to a Map

### Description

Draw a scalebar on an existing map.

### Usage

    mapScalebar(
      x,
      y = NULL,
      length,
      lwd = 1.5 * par("lwd"),
      cex = par("cex"),
      col = "black"
    )

### Arguments

`x, y` | position of the scalebar. Eventually this may be similar to the corresponding arguments in `legend()`, but at the moment `y` must be `NULL` and `x` must be `"topleft"`.
`length` | the distance to indicate, in kilometres. If not provided, a reasonable choice is made, based on the underlying map.
`lwd` | line width of the scalebar.
`cex` | character expansion factor for the scalebar text.
`col` | color of the scalebar.

### Details

The scale is appropriate to the centre of the plot, and will become increasingly inaccurate away from that spot, with the error depending on the projection and the fraction of the earth that is shown.

### Author(s)

Dan Kelley

### See Also

A map must first have been created with `mapPlot()`.

Other functions related to maps: `formatPosition()`, `lonlat2map()`, `lonlat2utm()`, `map2lonlat()`, `mapArrows()`, `mapAxis()`, `mapContour()`, `mapCoordinateSystem()`, `mapDirectionField()`, `mapGrid()`, `mapImage()`, `mapLines()`, `mapLocator()`, `mapLongitudeLatitudeXY()`, `mapPlot()`, `mapPoints()`, `mapPolygon()`, `mapText()`, `mapTissot()`, `oceCRS()`, `shiftLongitude()`, `usrLonLat()`, `utm2lonlat()`

### Examples

    library(oce)
    data(coastlineWorld)
    ## Arctic Ocean
    par(mar=c(2.5, 2.5, 1, 1))
    mapPlot(coastlineWorld, latitudelim=c(60, 120), longitudelim=c(-130,-50),
            col="lightgray", projection="+proj=stere +lat_0=90")
    mapScalebar()

[Package oce version 1.2-0 Index]