splitarrow() R function from [diagram]

adds a branched arrow between several points

connects two sets of points with a star-like structure, adds an arrowhead at a certain distance


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 centre=NULL.
...: other arguments passed to function straightarrow .

Returns

coordinates (x,y) where arrowheads are drawn

Author(s)

Karline Soetaert karline.soetaert@nioz.nl

Examples


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)

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:

"none" : skips the drawing of arrows.
"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 T-shaped (blunt) head.

The size of the arrow head can be specified with the arguments arr.length and arr.width.

See Arrowhead from package shape for details on arrow head.

splitarrow function