The arrows are drawn with directions on the graph that match the directions
indicated by the `u`

and `v`

components. The arrow size is set
relative to the units of the `y`

axis, according to the value of
`yscale`

, which has the unit of `v`

divided by the unit of
`y`

.
The interpretation of diagrams produced by `plotSticks`

can be
difficult, owing to overlap in the arrows. For this reason, it is often
a good idea to smooth `u`

and `v`

before using this function.

plotSticks(
x,
y,
u,
v,
yscale = 1,
add = FALSE,
length = 1/20,
mgp = getOption("oceMgp"),
mar = c(mgp[1] + 1, mgp[1] + 1, 1, 1 + par("cex")),
xlab = "",
ylab = "",
col = 1,
...
)

## Arguments

x |
x coordinates of stick origins. |

y |
y coordinates of stick origins. If not supplied, 0 will be used;
if length is less than that of x, the first number is repeated and the rest
are ignored. |

u |
x component of stick length. |

v |
y component of stick length. |

yscale |
scale from u and v to y (see “Description”). |

add |
boolean, set `TRUE` to add to an existing plot. |

length |
value to be provided to `arrows()` ; here, we set a
default that is smaller than normally used, because these plots tend to be
crowded in oceanographic applications. |

mgp |
3-element numerical vector to use for `par` `("mgp")` . Note
that the default `mar` is computed from the `mgp` value.
The default is tighter than the R
default, in order to use more space for the data and less for the axes. |

mar |
value to be used with `par` `("mar")` . |

xlab, ylab |
labels for the plot axes. The default is not to label them. |

col |
color of sticks, in either numerical or character format. This is
made to have length matching that of `x` by a call to `rep()` ,
which can be handy in e.g. colorizing a velocity field by day. |

... |
graphical parameters passed down to `arrows()` . It
is common, for example, to use smaller arrow heads than `arrows()`
uses; see “Examples”. |

## Examples

plotSticks(t, 99, u, v, yscale=25, add=TRUE)