# Ksector

From spatstat v1.42-2
by Adrian Baddeley

##### Sector K-function

A directional counterpart of Ripley's $K$ function, in which pairs of points are counted only when the vector joining the pair happens to lie in a particular range of angles.

- Keywords
- spatial, nonparametric

##### Usage

```
Ksector(X, begin = 0, end = 360, ...,
units = c("degrees", "radians"),
r = NULL, breaks = NULL,
correction = c("border", "isotropic", "Ripley", "translate"),
domain=NULL, ratio = FALSE, verbose=TRUE)
```

##### Arguments

- X
- The observed point pattern,
from which an estimate of $K(r)$ will be computed.
An object of class
`"ppp"`

, or data in any format acceptable to`as.ppp()`

. - begin,end
- Numeric values giving the range of angles inside which
points will be counted. Angles are measured in degrees
(if
`units="degrees"`

, the default) or radians (if`units="radians"`

) anti-clockwise from the positive $x$-axis - ...
- Ignored.
- units
- Units in which the angles
`begin`

and`end`

are expressed. - r
- Optional. Vector of values for the argument $r$ at which $K(r)$
should be evaluated. Users are advised
*not*to specify this argument; there is a sensible default. - breaks
- This argument is for internal use only.
- correction
- Optional. A character vector containing any selection of the
options
`"none"`

,`"border"`

,`"bord.modif"`

,`"isotropic"`

,`"Ripley"`

,`"translate"`

,`"translation"`

, - domain
- Optional window. The first point $x_i$ of each pair of points
will be constrained to lie in
`domain`

. - ratio
- Logical.
If
`TRUE`

, the numerator and denominator of each edge-corrected estimate will also be saved, for use in analysing replicated point patterns. - verbose
- Logical value indicating whether to print progress reports and warnings.

##### Details

This is a directional counterpart of Ripley's $K$ function
(see `Kest`

) in which, instead of counting all
pairs of points within a specified distance $r$, we
count only the pairs $(x_i, x_j)$
for which the vector $x_j - x_i$
falls in a particular range of angles.

This can be used to evaluate evidence for anisotropy
in the point pattern `X`

.

##### Value

- An object of class
`"fv"`

containing the estimated function.

##### See Also

##### Examples

```
K <- Ksector(swedishpines, 0, 90)
plot(K)
```

*Documentation reproduced from package spatstat, version 1.42-2, License: GPL (>= 2)*

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