subset.mask {secr}

Subset, Split or Combine Mask Objects

Description

Retain selected rows of a mask object.

Usage

## S3 method for class 'mask'
subset(x, subset, ...)

## S3 method for class 'mask'
split(x, f, drop = FALSE, clusters = NULL, ...)

## S3 method for class 'mask'
rbind(...)

Arguments

x

mask object

subset

numeric or logical vector to select rows of mask

f

factor or object that may be coerced to a factor

drop

logical indicating if levels that do not occur should be dropped (if f is a factor)

clusters

list of traps objects, each defining a cluster (alternative to f)

...

two or more mask objects (rbind only)

Details

The subscripts in subset may be of type integer, character or logical as described in Extract.

The split method may use either a factor f with one value for each row or a list of clusters, each a traps object. The output mask corresponding to each cluster is the subset of the original mask points that lie within buffer of a trap within the cluster; buffer is computed as the maximum distance between a mask point in x and any detector in clusters. Sub-masks specified with clusters may overlap.

Covariates are ignored by rbind.mask.

Value

For subset, an object of class ‘mask’ with only the requested subset of rows and ‘type’ attribute set to ‘subset’.

For split, a list of mask objects.

For rbind, an object of class ‘mask’ with all unique rows from the masks in ..., and ‘type’ attribute set to ‘rbind’.

Warning

The spacing attribute is carried over from the input (it is not updated automatically). In the case of very sparse masks (i.e. those with isolated points) this may lead to an unexpected value for this attribute. (Automatic updating requires excessive computation time and/or memory for very large masks).

See Also

mask

Examples

tempmask <- make.mask(make.grid())
OK <- (tempmask$x + tempmask$y) > 100
tempmask <- subset(tempmask, subset = OK)
plot(tempmask)