secr (version 1.3.0)

read.traps: Read Detector Data From File

Description

Construct an object of class traps with detector locations from a text file or data frame. Usage per occasion and covariates may be included.

Usage

read.traps(file = NULL, data = NULL, detector = "multi", ...)

Arguments

file

character string with name of text file

data

data frame of detector coordinates

detector

character string for detector type

...

other arguments to pass to read.table

Value

• An object of class traps comprising a data frame of x- and y-coordinates, the detector type ('single', 'multi', or 'proximity'), and possibly other attributes.

Details

Reads a text file in which the first column is a character string identifying a detector and the next two columns are its x- and y-coordinates, separated by white space. The coordinates optionally may be followed by a string of codes '0' or '1' indicating whether the detector was operated on each occasion. A single trap-specific numeric covariate is allowed; it should be at the end of the line preceded by '/'. This format is compatible with the Density software (Efford 2007), except that all detectors are assumed to be of the same type (usage codes greater than 1 are treated as 1). If file is missing then x-y coordinates will be taken instead from data. This option does not allow for covariates or usage, but they maybe added later. detector specifies the behaviour of the detector following Efford et al. (2009). 'single' refers to a trap that is able to catch at most one animal at a time; 'multi' refers to a trap that may catch more than one animal at a time. For both 'single' and 'multi' detectors a trapped animals can appear at only one detector per occasion. Detectors of type 'proximity', such as camera traps and hair snags for DNA sampling, allow animals to be recorded at several detectors on one occasion.

References

Efford, M. G. (2007) Density 4.1: software for spatially explicit capture--recapture. Department of Zoology, University of Otago, Dunedin, New Zealand. http://www.otago.ac.nz/density Efford, M. G., Borchers D. L. and Byrom, A. E. (2009) Density estimation by spatially explicit capture-recapture: likelihood-based methods. In: D. L. Thomson, E. G. Cooch and M. J. Conroy (eds) Modeling Demographic Processes in Marked Populations. Springer, New York. Pp. 255--269.

See Also

traps, make.grid

Examples

## Replace file name with a valid local name and remove '#' 
# read.traps ('c:\\\\myfolder\\\\mytraps.txt', detector='proximity')
## 'mytraps.txt' should have lines like this 
# 1     365     365
# 2     365     395
# 3     365     425
# etc.