A CRS object, proj4 string, or an object from which a projection
can be extracted with proj4string(crs)
pos
Position, as specified in the legend function.
cex
scaling factor for the legend
pt.cex
Scaling factor north arrow (can be zero).
seg.len
approximate length (in character units) of the scale bar. can be zero.
title.cex
scaling for the distance text
outer
If TRUE, put bar or map in the margin of the plot
map
Either a Raster for the inset map or a string
passed to openmap's path argument
zoom
Zoom level if retrieving inset map from openmap
width
Width of the inset map, as a fraction of the plot window
col
Colour for shaded region of inset map
borderMap
border style for the inset map (passed to polygon)
cropInset
Crop the insert map to this extent
...
Additional arguments passed to legend for scaleBar
or polygon (for insetMap).
Details
scaleBar produces a scale bar reflecting the distance travelling on a great circle
from the centre of the plot and travelling to the right. The length of the bar is the width
of 6 characters times scale.cex.