# Count Number of Instances of Points

`multiplicity.Spatial.Rd`

The generic function `multiplicity`

defined in spatstat.geom is
intended to count the number of duplicates of each element of an object.
spatstat.geom already offers methods for point patterns, matrices and
data frames, and here we add a method for `Spatial`

objects from
the sp package. It is a wrapper for the default method, which
effectively computes the distance matrix of the points,
and then just counts the number of zeroes in each row.

## Usage

```
# S3 method for class 'Spatial'
multiplicity(x)
```

## Arguments

- x
a

`"Spatial"`

object (we only need a`coordinates`

-method), e.g. of class`"SpatialPoints"`

.

## See also

`multiplicity`

in package spatstat.geom.
See the Examples of the `hagelloch`

data for a specific
use of `multiplicity`

.

## Examples

```
foo <- SpatialPoints(matrix(c(1,2,
2,3,
1,2,
4,5), 4, 2, byrow=TRUE))
multiplicity(foo)
# the following function determines the multiplicities in a matrix
# or data frame and returns unique rows with appended multiplicity
countunique <- function(x) unique(cbind(x, count=multiplicity(x)))
countunique(coordinates(foo))
```