traps.info {secr} | R Documentation

## Detector Attributes

### Description

Extract or replace attributes of an object of class 'traps'.

### Usage

    polyID(object)
    polyID(object) <- value
    transectID(object)
    transectID(object) <- value
    searcharea(object)
    searcharea(object) <- value
    transectlength(object)

### Arguments

`object` | a 'traps' object
`value` | replacement value (see Details)

### Details

The 'polyID' and 'transectID' functions assign and extract the attribute of a 'traps' object that relates vertices (rows) to particular polygons or transects. The replacement value should be a factor of length equal to nrow(object).

The 'searcharea' attribute of a 'quadratbinary' or 'quadratcount' traps object is the area in hectares searched at each detector point (quadrat). Usually, this is the area of a rectangular pixel determined by the detector spacing (spacex, spacey). Replacement creates square pixels with dimensions spacex = spacey = value^0.5 * 100.

The 'searcharea' of a 'polygon' traps object is a vector of the areas of the component polygons. This is a read-only value (i.e. 'searcharea<-' does not apply).

The 'transectlength' of a 'transect' traps object is a vector of the lengths of the component transects in metres. This is a read-only value.

### Value

`polyID` - a factor with one level per polygon. `searcharea` - numeric value of quadrat area or polygon areas, in hectares. `transectlength` - numeric value of transect lengths, in metres.

### Author(s)

Murray Efford murray.efford@otago.ac.nz

### See Also

`traps`

### Examples

    ## default is a single polygon
    temp <- make.grid(detector = 'polygon', hollow = TRUE)
    polyID(temp)
    plot(temp)

    ## split in two
    temp <- make.grid(detector = 'polygon', hollow = TRUE)
    polyID(temp) <- factor(rep(c(1,2),rep(10,2)))
    plot(temp)

[Package secr version 1.3.0 Index]