# 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 using`as.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)
# }
```

*Documentation reproduced from package spatstat, version 1.61-0, License: GPL (>= 2)*