adds a branched arrow between several points
Description
connects two sets of points with a starlike structure, adds an arrowhead at a certain distance
Usage
1 2  splitarrow(from, to, lwd = 2, lty = 1, lcol = "black", arr.col = lcol,
arr.side = 2, arr.pos = 0.5, centre = NULL, dd = 0.5, ...)

Arguments
from 
matrix of coordinates (x,y) of points *from* which to draw arrow. 
to 
matrix of coordinates (x,y) of points *to* which to draw arrow. 
lwd 
line width. 
lty 
line type. 
lcol 
line color. 
arr.col 
arrow color. 
arr.side 
segment number on which arrowhead is drawn (1,2). 
arr.pos 
relative position of arrowhead on segment on which arrowhead is drawn. 
centre 
coordinates (x,y) of central point. 
dd 
relative position of central point, only when 
... 
other arguments passed to function straightarrow. 
Details
a branched arrow is drawn between points '(from
, to
)',
where both from
and to
can be several points.
The arrow segments radiate into a central point. Either the (x,y)
coordinates of this central point are set with centre
or
it is estimated at a certain distance (dd
>0,<1) between the
centroid of the *from
* points and the centroid of the *to
*
points.
The segment(s) on which the arrow head is drawn is set with arr.side
,
which is one or more values in (1, 2)

arr.side=1
sets the arrow head on the segment *from* > central point 
arr.side=2
sets the arrow head on the segment central point > *to*
The position of the arrowhead on the segment on which it is drawn,
is set with arr.pos
, a value between 0(start of segment) and
1(end of segment)
The type of the arrowhead is set with arr.type
which can take the
values:
"simple" : uses comparable R function
arrows
."triangle": uses filled triangle.
"curved" : draws arrowhead with curved edges.
"circle" : draws circular head.
"ellipse" : draws ellepsoid head
"T" : draws Tshaped (blunt) head
see Arrowhead
from package shape for details on
arrow head.
Value
coordinates (x,y) where arrowheads are drawn
Author(s)
Karline Soetaert <karline.soetaert@nioz.nl>
See Also
straightarrow
, segmentarrow
,
curvedarrow
, selfarrow
, bentarrow
,
treearrow
,
arrows
: the comparable R function,
Arrows
: more complicated arrow function from package
shape.
Examples
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24  openplotmat(main = "splitarrow")
pos < coordinates(c(1, 2, 2, 4, 1))
splitarrow(from = pos[1, ], to = pos[2:10, ],
arr.side = 1, centre = c(0.5, 0.625))
for (i in 1:10)
textrect(pos[i, ], lab = i, cex = 2, radx = 0.05)
openplotmat(main = "splitarrow")
pos < coordinates(c(1, 3))
splitarrow(from = pos[1,], to = pos[2:4, ], arr.side = 1)
splitarrow(from = pos[1,], to = pos[2:4, ], arr.side = 2)
for (i in 1:4)
textrect(pos[i, ], lab = i, cex = 2, radx = 0.05)
openplotmat(main = "splitarrow")
pos < coordinates(N = 6)
pos < rbind(c(0.5, 0.5), pos)
splitarrow(from = pos[1, ], to = pos[2:7, ], arr.side = 2)
for (i in 1:7)
textrect(pos[i, ], lab = i, cex = 2, radx = 0.05)
