oce (version 1.2-0)

mapScalebar: 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.

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

# NOT RUN {
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()
# }
# NOT RUN {
# }