For each point in the set being tessellated produces a list entry describing the Dirichlet/Voronoi tile containing that point.
tile.list(object,minEdgeLength=NULL)
An object of class deldir
as produced
by the function deldir()
.
Positive numeric scalar specifying the minimum length that
an edge of a tile may have. It is used to eliminate edges
that are effectively of zero length, which can cause tiles
to be “invalid”. This argument defaults to
sqrt(.Machine$double.eps)
time the diameter (length
of the diagonal) of the “rectangular window”
associated with the tessellation. This rectangular window
is available as the rw
component of object
.
A list with one entry for each of the points in the set being tesselated. Each entry is in turn a list with components
The index of the point in the original sequence of points
that is being tessellated. Note that if a point is one of a set
of duplicated points then ptNum
is the first of the
indices of the points in this set.
The coordinates of the point whose tile is being described.
The “type” of the pt
, either “data”
or “dummy”. Present only if any dummy points were specified
in the call to deldir()
.
The x
coordinates of the vertices of the tile, in
anticlockwise order.
The y
coordinates of the vertices of the tile, in
anticlockwise order.
Vector of logicals indicating whether the tile vertex is a ``real'' vertex, or a boundary point, i.e. a point where the tile edge intersects the boundary of the enclosing rectangle.
The “auxiliary value” or “weight” associated
with the pt
; present only if such values were supplied in
the call to deldir()
.
The area of the tile.
The author expresses sincere thanks to Majid Yazdani who found and
pointed out a serious bug in tile.list
in a previous version
(0.0-5) of the deldir
package.
The set of vertices of each tile may be ``incomplete''. Only vertices which lie within the enclosing rectangle, and ``boundary points'' are listed.
Note that the enclosing rectangle may be specified by the user
in the call to deldir()
.
In contrast to some earlier versions of deldir
, the corners
of the enclosing rectangle are now include as vertices of tiles.
I.e. a tile which in fact extends beyond the rectangular window
and contains a corner of that window will have that corner added
to its list of vertices. Thus the corresponding polygon is the
intersection of the tile with the enclosing rectangle.
deldir()
, plot.tile.list()
triang.list()
plot.triang.list()
# NOT RUN {
x <- runif(20)
y <- runif(20)
z <- deldir(x,y)
w <- tile.list(z)
z <- deldir(x,y,rw=c(0,1,0,1))
w <- tile.list(z)
z <- deldir(x,y,rw=c(0,1,0,1),dpl=list(ndx=2,ndy=2))
w <- tile.list(z)
# }
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