# areaLoss

##### Difference of Disc Areas

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`

.

##### See Also

##### Examples

```
# NOT RUN {
data(cells)
areaLoss(cells, 0.1)
# }
```

*Documentation reproduced from package spatstat, version 1.60-1, License: GPL (>= 2)*