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.
mapCoordinateSystem(longitude, latitude, L = 100, phi = 0, ...)numeric vector of longitudes in degrees.
numeric vector of latitudes in degrees.
axis length in km.
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.
This is a preliminary version of this function. It only works if the lines of constant latitude are horizontal on the plot.
library(oce)
if (requireNamespace("ocedata", quietly=TRUE)) {
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)
}
Other functions related to maps:
formatPosition(),
lonlat2map(),
lonlat2utm(),
map2lonlat(),
mapArrows(),
mapAxis(),
mapContour(),
mapDirectionField(),
mapGrid(),
mapImage(),
mapLines(),
mapLocator(),
mapLongitudeLatitudeXY(),
mapPlot(),
mapPoints(),
mapPolygon(),
mapScalebar(),
mapText(),
mapTissot(),
oceCRS(),
oceProject(),
shiftLongitude(),
usrLonLat(),
utm2lonlat()