# with.ssf

##### Evaluate Expression in a Spatially Sampled Function

Given a spatially sampled function, evaluate an expression involving the function values.

- Keywords
- manip, spatial, programming

##### Usage

`apply.ssf(X, …)` # S3 method for ssf
with(data, …)

##### Arguments

- X, data
A spatially sampled function (object of class

`"ssf"`

).- …
Arguments passed to

`with.default`

or`apply`

specifying what to compute.

##### Details

An object of class `"ssf"`

represents a
function (real- or vector-valued) that has been
sampled at a finite set of points.
It contains a data frame
which provides the function values
at the sample points.

In `with.ssf`

, the expression specified by `…`

will be evaluated in this dataframe.
In `apply.ssf`

, the dataframe will be subjected to
the `apply`

operator using the additional arguments
`…`

.

If the result of evaluation
is a data frame with one row for each data point,
or a numeric vector with one entry for each data point,
then the result will be an object of class `"ssf"`

containing this information. Otherwise, the result will be
a numeric vector.

##### Value

An object of class `"ssf"`

or a numeric vector.

##### See Also

##### Examples

```
# NOT RUN {
a <- ssf(cells, data.frame(d=nndist(cells), i=1:npoints(cells)))
with(a, i/d)
# }
```

*Documentation reproduced from package spatstat, version 1.56-1, License: GPL (>= 2)*