OceanView (version 1.0.2)

vector plots: Vector velocity plot.

Description

Displays (velocity) vectors as segments.

Usage

vectorplot(u, v, x = 0, y = 0, colvar = NULL, ...,
           col = NULL, NAcol = "white", colkey = NULL, 
           by = 1, arr = FALSE, xfac = NULL, 
           clim = NULL, clab = NULL, add = FALSE)

Arguments

u

A vector with quantities (velocities) in x-direction.

v

A vector with quantities (velocities) in y-direction. Should have the same length as u

x

A vector with x-axis values. If 0, everything will be radiating from the origin. Usually x will be equal to time.

y

The y-axis value. One number, or a vector of length = u.

colvar

The variable used for coloring. It need not be present, but if specified, it should be a vector of dimension equal to c(nrow(u), ncol(v)). Values of NULL, NA, or FALSE will toggl

col

Colors to be used for coloring the arrows as specified by the colvar variable. If col is NULL and colvar is specified, then a red-yellow-blue colorscheme (

NAcol

Colors to be used for colvar values that are NA.

colkey

A logical, NULL (default), or a list with parameters for the color key (legend). List parameters should be one of side, plot, length, width, dist, shift, addlines, col.clab, cex.clab, side.clab, line.clab

clim

Only if colvar is specified, the range of the colors, used for the color key.

clab

Only if colkey is not NULL or FALSE, the label to be written on top of the color key. The label will be written at the same level as the main title. To lower it, clab can be made a ve

by

Number increment for plotting vectors. Set this to an integer > 1 if the vector density is too high.

xfac

Only for x not NULL, the proportionality factor with which the vectors on the x-axis must be drawn. A value of 1 means that the distance of one will be drawn as one x-unit on the x-axis. For a value of

arr

If TRUE, then Arrows will be drawn; if FALSE, segments will be drawn.

add

If TRUE, will add to the current plot.

...

additional arguments passed to the plotting methods.

Value

• none

See Also

quiver2D, flowpath, for other functions to plot velocities.

Examples

# save plotting parameters
 mf <- par("mfrow")

## =======================================================================
##  EXAMPLE 1: 
## =======================================================================

 par(mfrow = c(2, 2))

 u <- cos(seq(0, 2*pi, 0.1))
 v <- sin(seq(0, 2*pi, 0.1)+ 1)

 vectorplot(u = u, v = v)
 vectorplot(u = u, v = v, col = 1:10)

 x <- seq(0, 1, length.out = length(u))
 vectorplot(u = u, v = v, x = x, xfac = 3)
 points(x, rep(0, length(u)), pch = "+", col = "red")

 vectorplot(u = u, v = v, x = 1:length(u), xfac = 10)

## =======================================================================
##  EXAMPLE 2:  adding to a plot
## =======================================================================

 par(mfrow = c(2, 2))
 x <- 1:length(u)
 plot(x, u)
 vectorplot(u = u, v = v, x = x, xfac = 10, 
            add = TRUE, col = "red")
 
 vectorplot(u = u, v = v, x = x, xfac = 10, 
   colvar = sqrt(u^2+v^2), clab = "m/s")
 
 vectorplot(u = u, v = v, x = x, xfac = 10, 
   colvar = sqrt(u^2+v^2), clab = "m/s", log = "c")

# reset plotting parameters
 par(mfrow = mf)