oce (version 1.0-1)

mapCoordinateSystem: Draw a coordinate system

Description

Draws arrows on a map to indicate a coordinate system, e.g. for an to indicate a coordinate system set up so that one axis is parallel to a coastline.

Usage

mapCoordinateSystem(longitude, latitude, L = 100, phi = 0, ...)

Arguments

longitude

numeric value of longitude in degrees.

latitude

numeric value of latitude in degrees.

L

axis length in km.

phi

angle, in degrees counterclockwise, that the "x" axis makes to a line of latitude.

...

plotting arguments, passed to mapArrows; see “Examples” for how to control the arrow-head size.

Details

This is a preliminary version of this function. It only works if the lines of constant latitude are horizontal on the plot.

Examples

# NOT RUN {
library(oce)
data(coastlineWorldFine, package='ocedata')
HfxLon <- -63.5752
HfxLat <- 44.6488
mapPlot(coastlineWorldFine, proj='+proj=merc',
        longitudelim=HfxLon+c(-2,2), latitudelim=HfxLat+c(-2,2),
        col='lightgrey')
mapCoordinateSystem(HfxLon, HfxLat, phi=45, length=0.05)
# }