formatDistData: Convert individual-level distance data to the transect-level format required by distsamp

Description

Convert individual-level distance data to the transect-level format required by distsamp

Usage

formatDistData(distData, distCol, transectNameCol, dist.breaks)

Arguments

distData

data.frame where each row is a detected individual. Must have at least 2 columns. One for distances and the other for transect names.

distCol

character, the column name containing distances

transectNameCol

character, column name containing transect names

dist.breaks

numeric vector of distance interval cutpoints. Length must equal J+1.

Value

An M x J data.frame containing the tabulated detections in each distance interval for each transect. Transect names will become rownames and colnames will be y.1, y.2, ..., y.J.

Details

This function creates a site (M) by distance interval (J) response matrix from a data.frame containing the detection distances for each individual and the transect names.

Examples

Run this code

# Create a data.frame containing distances of animals detected
# along 4 transects.
dat <- data.frame(transect=gl(4,5, labels=letters[1:4]), distance=rpois(20, 10))
dat

# Look at your transect names.
levels(dat$transect)

# Suppose that you also surveyed a transect named "e" where no animals were
# detected. You must add it to the levels of dat$transect
levels(dat$transect) <- c(levels(dat$transect), "e")
levels(dat$transect)

# Distance cut points defining distance intervals
cp <- c(6, 8, 10, 12, 14, 18)

# Create formated response data.frame
yDat <- formatDistData(dat, "distance", "transect", cp) 
yDat

# Now you could merge yDat with transect-level covariates and 
# then use unmarkedFrameDS to prepare data for distsamp}