mapDirectionField {oce} | R Documentation |
Plot a direction field on a existing map.
mapDirectionField(longitude, latitude, u, v, scale = 1, length = 0.05, code = 2, col = par("fg"), ...)
longitude, latitude |
vectors of the starting points for arrows. |
u, v |
components of a vector to be shown as a direction field. |
scale |
latitude degrees per unit of |
length |
length of arrow heads, passed to |
code |
code of arrows, passed to |
col |
colour of arrows. This may be a single colour, or a matrix
of colours of the same dimension as |
... |
optional arguments passed to |
Adds arrows for a direction field on an existing map. There are different
possibilities for how longitude
, latitude
and u
and
v
match up. In one common case, all four of these are matrices, e.g.
output from a numerical model. In another, longitude
and
latitude
are the coordinates along the matrices, and are thus stored in
vectors with lengths that match appropriately.
Dan Kelley
A map must first have been created with mapPlot
.
Other functions related to maps: lonlat2map
,
lonlat2utm
, map2lonlat
,
mapArrows
, mapAxis
,
mapContour
, mapGrid
,
mapImage
, mapLines
,
mapLocator
,
mapLongitudeLatitudeXY
,
mapPlot
, mapPoints
,
mapPolygon
, mapScalebar
,
mapText
, mapTissot
,
oceCRS
, shiftLongitude
,
utm2lonlat
## Not run: library(oce) data(coastlineWorld) par(mar=rep(2, 4)) mapPlot(coastlineWorld, longitudelim=c(-120,-55), latitudelim=c(35, 50), proj="+proj=laea +lat0=40 +lat1=60" +lon_0=-110) lon <- seq(-120, -60, 15) lat <- 45 + seq(-15, 15, 5) lonm <- matrix(expand.grid(lon, lat)[, 1], nrow=length(lon)) latm <- matrix(expand.grid(lon, lat)[, 2], nrow=length(lon)) ## vectors pointed 45 degrees clockwise from north u <- matrix(1/sqrt(2), nrow=length(lon), ncol=length(lat)) v <- matrix(1/sqrt(2), nrow=length(lon), ncol=length(lat)) mapDirectionField(lon, lat, u, v, scale=3) mapDirectionField(lonm, latm, 0, 1, scale=3, col='red') # Color code by longitude, using thick lines col <- colormap(lonm)$zcol mapDirectionField(lonm, latm, 1, 0, scale=3, col=col, lwd=2) ## End(Not run)