R: Difference of Disc Areas

areaLoss {spatstat.geom} | R Documentation

## Difference of Disc Areas

### Description

Computes the area of that part of a disc that is not covered by other discs.

### Usage

       areaLoss(X, r, ..., W=as.owin(X), subset=NULL,
                     exact=FALSE,
                     ngrid=spatstat.options("ngrid.disc"))

### Arguments

`X` | Locations of the centres of discs. A point pattern (object of class `"ppp"`).
`r` | Disc radius, or vector of disc radii.
`...` | Ignored.
`W` | Optional. Window (object of class `"owin"`) inside which the area should be calculated.
`subset` | Optional. Index identifying a subset of the points of `X` for which the area difference should be computed.
`exact` | Choice of algorithm. If `exact=TRUE`, areas are computed exactly using analytic geometry. If `exact=FALSE` then a faster algorithm is used to compute a discrete approximation to the areas.
`ngrid` | Integer. Number of points in the square grid used to compute the discrete approximation, when `exact=FALSE`.

### Details

This function computes, for each point `X[i]` in `X` and for each radius `r`, the area of that part of the disc of radius `r` centred at the location `X[i]` that is not covered by any of the other discs of radius `r` centred at the points `X[j]` for `j` not equal to `i`. This area is important in some calculations related to the area-interaction model `AreaInter`.

The result is a matrix, with one row for each point in `X` and one column for each entry of `r`.

### Value

A matrix with one row for each point in `X` (or `X[subset]`) and one column for each value in `r`.

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz

### See Also

`AreaInter`, `areaGain`, `dilated.areas`

### Examples

       areaLoss(cells, 0.1)

[Package spatstat.geom version 2.3-2 Index]