polartess
Tessellation Using Polar Coordinates
Create a tessellation with tiles defined by polar coordinates (radius and angle).
Usage
polartess(W, …, nradial = NULL, nangular = NULL,
radii = NULL, angles = NULL,
origin = NULL, sep = "x")
Arguments
- W
A window (object of class
"owin"
) or anything that can be coerced to a window usingas.owin
, such as a point pattern.- …
Ignored.
- nradial
Number of tiles in the radial direction. A single integer. Ignored if
radii
is given.- nangular
Number of tiles in the angular coordinate. A single integer. Ignored if
angles
is given.- radii
The numeric values of the radii, defining the tiles in the radial direction. A numeric vector, of length at least 2, containing nonnegative numbers in increasing order. The value
Inf
is permitted.- angles
The numeric values of the angles defining the tiles in the angular coordinate. A numeric vector, of length at least 2, in increasing order, containing angles in radians.
- origin
Location to be used as the origin of the polar coordinates. Either a numeric vector of length 2 giving the spatial location of the origin, or one of the strings
"centroid"
,"midpoint"
,"left"
,"right"
,"top"
,"bottom"
,"topleft"
,"bottomleft"
,"topright"
or"bottomright"
indicating the location in the window.- sep
Argument passed to
intersect.tess
specifying the character string to be used as a separator when forming the names of the tiles.
Details
A tessellation will be formed from tiles defined by intervals in the polar coordinates \(r\) (radial distance from the origin) or \(\theta\) (angle from the horizontal axis) or both. These tiles look like the cells on a dartboard.
If the argument radii
is given, tiles will be demarcated
by circles centred at the origin, with the specified radii.
If radii
is absent but nradial
is given,
then radii
will default to a sequence
of nradial+1
radii equally spaced from zero to the maximum
possible radius. If neither radii
nor nradial
are given,
the tessellation will not include circular arc boundaries.
If the argument angles
is given, tiles will be demarcated
by lines emanating from the origin at the specified angles.
The angular values can be any real numbers; they will be interpreted
as angles in radians modulo 2*pi
,
but they must be an increasing sequence of numbers.
If angles
is absent but nangular
is given,
then angles
will default to a sequence
of nangular+1
angles equally spaced from 0 to 2*pi
.
If neither angles
nor nangular
are given,
the tessellation will not include linear boundaries.
Value
A tessellation (object of class "tess"
).
See Also
To construct other kinds of tessellations, see
tess
,
quadrats
, hextess
,
venn.tess
,
dirichlet
, delaunay
, quantess
and rpoislinetess
.
Examples
# NOT RUN {
Y <- c(2.8, 1.5)
plot(polartess(letterR, nangular=6, radii=(0:4)/2, origin=Y),
do.col=TRUE)
# }