Function triangulate
decomposes a simple polygon (optionally having holes) into contiguous triangles.
triangulate(outer.poly, holes)
A list of 6 variables, suitable for using in swin
and spp
, and giving the vertices coordinates \((ax,ay,bx,by,cx,cy)\) of the triangles that
pave the polygon. For a polygon with t holes totaling \(n\) vertices (outer contour + holes), the number of triangles produced
is \((n-2)+2t\), with \(n<200\) in this version of the program.
a list with two component vectors x
and y
giving vertex coordinates of the polygon
or a vector (xmin,ymin,xmax,ymax)
giving coordinates \((ximn,ymin)\) and \((xmax,ymax)\) of the origin and the
opposite corner of a rectangle sampling window (see swin
).
(optional) a list (or a list of list) with two component vectors x
and y
giving vertices
coordinates of inner polygon(s) delineating hole(s) within the outer.poly
.
In argument outer.poly
, the vertices must be listed following boundary of the polygon without any repetition (i.e. do not repeat the first vertex).
Argument holes
may be a list of vertices coordinates of a single hole (i.e. with \(x\) and \(y\) component vectors) or a list of list for multiple holes,
where each holes[[i]]
is a list with \(x\) and \(y\) component vectors. Holes' vertices must all be inside the outer.poly
boundary (vertices on the boundary
are considered outside). Multiple holes do not overlap each others.
Goreaud, F. and P?Pelissier, R. 1999. On explicit formula of edge effect correction for Ripley's K-function. Journal of Vegetation Science, 10:433-438.
Narkhede, A. & Manocha, D. 1995. Fast polygon triangulation based on Seidel's algorithm. Pp 394-397 In A.W. Paeth (Ed.)
Graphics Gems V. Academic Press. http://www.cs.unc.edu/~dm/CODE/GEM/chapter.html.
spp
,
swin