TriangleCentres {Ternary} | R Documentation |
Coordinates of triangle mid-points
Description
Calculate x and y coordinates of the midpoints of triangles tiled to cover a ternary plot.
Usage
TriangleCentres(resolution = 48L, direction = getOption("ternDirection", 1L))
Arguments
resolution |
The number of triangles whose base should lie on the longest axis of the triangle. Higher numbers will result in smaller subdivisions and smoother colour gradients, but at a computational cost. |
direction |
(optional) Integer specifying the direction that the current ternary plot should point: 1, up; 2, right; 3, down; 4, left. |
Value
TriangleCentres()
returns a matrix with three named rows:
-
x
x coordinates of triangle midpoints; -
y
y coordinates of triangle midpoints; -
triDown
0
for upwards-pointing triangles,1
for downwards-pointing.
Author(s)
Martin R. Smith (martin.smith@durham.ac.uk)
See Also
Add triangles to a plot: TernaryTiles()
Other coordinate translation functions:
ReflectedEquivalents()
,
TernaryCoords()
,
XYToTernary()
Other tiling functions:
Polygon-Geometry
,
TriangleInHull()
Examples
TernaryPlot(grid.lines = 4)
centres <- TriangleCentres(4)
text(centres["x", ], centres["y", ], ifelse(centres["triDown", ], "v", "^"))