Vertices and Edges of Dirichlet Tessellation
Computes the Dirichlet-Voronoi tessellation of a point pattern and extracts the vertices or edges of the tiles.
dirichletVertices(X) dirichletEdges(X, clip=TRUE)
X |
Point pattern (object of class |
clip |
Logical value specifying whether to clip the tile edges to the window. See Details. |
These function compute the Dirichlet-Voronoi tessellation of X
(see dirichlet
)
and extract the vertices or edges of the tiles of the tessellation.
The Dirichlet vertices are the spatial locations which are locally
farthest away from X
, that is, where the distance function
of X
reaches a local maximum.
The Dirichlet edges are the dividing lines equally distant between
a pair of points of X
.
The Dirichlet tessellation of X
is computed
using dirichlet
. The vertices or edges of all
tiles of the tessellation are extracted.
For dirichletVertices
, any vertex which
lies on the boundary of the window of X
is deleted.
The remaining vertices are returned, as a point pattern,
without duplicated entries.
For dirichletEdges
, the edges are initially computed
inside the rectangle Frame(X)
.
Then if clip=TRUE
(the default), these edges are intersected
with Window(X)
, which may cause an edge to be broken into
several pieces.
dirichletVertices
returns a point pattern (object of class "ppp"
) in the same window
as X
.
dirichletEdges
returns a line segment pattern (object of
class "psp"
).
Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.
plot(dirichlet(cells)) plot(dirichletVertices(cells), add=TRUE) ed <- dirichletEdges(cells)
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