VTrack (version 1.10)

NonResidenceExtractId: Extract the Non-residence Events, the Corresponding Distance Moved and the Rate of Movement

Description

This function creates a nonresidences data frame from a residences event data frame and a optional distance matrix (sDistanceMatrix). This function is not mandatory as it is carried out automatically if the user provides a distance matrix in the sDistanceMatrix field when running the RunResidenceExtraction function.

Usage

NonResidenceExtractId(sResidenceEventFile, sDistanceMatrix = NULL)

Arguments

sResidenceEventFile

a residence event table

sDistanceMatrix

an optional two dimentional array (matrix) containing the pairwise distances between a series of receivers

Value

• STARTTIME
  a POSIXct vector object containing the date and time a transmitter left a receiver/station after a residence event
• ENDTIME
  a POSIXct vector object containing the date and time a transmitter arrived at a receiver/station and a new residence event was logged
• NONRESIDENCEEVENT
  a numeric vector indexing each nonresidence event
• TRANSMITTERID
  a numeric or character vector indexing the transmitter from which nonresidence events were determined
• RECEIVERID1
  a numeric or character vector indexing the receiver which the transmitter initially moved from. If STATIONNAME is specified in the function, STATIONNAME1 is returned
• RECEIVERID2
  a numeric or character vector indexing the receiver which the transmitter moved to. If STATIONNAME is specified in the function, STATIONNAME2 is returned
• DURATION
  a numeric vector containing the total time in seconds taken for the transmitter to move between two receivers or stations
• DISTANCE
  a numeric vector containing the minimum distance travelled in meters between two receivers/stations according to the distance matrix. If a distance matrix was not attached (=NULL), distance is returned as 0
• ROM
  a numeric vector containing the rate of movement (ROM) in m/s. This is calculated from the distance travelled (i.e. DISTANCE) divided by the time taken to move between the receivers (i.e. DURATION)

See Also

RunResidenceExtraction

Examples

# This function runs within the RunResidenceExtraction function when 
# a distance matrix is provided by the user.

# Extract residence events at RECEIVERS from the VTrack-transformed 
# saltwater crocodile archive

# Load the crocodile data into the VTrack archive
data(crocs)  
Vcrocs <- ReadInputData(infile=crocs,
                        iHoursToAdd=10,
                        fAATAMS=FALSE,
                        fVemcoDualSensor=FALSE,
                        dateformat = NULL,
                        sVemcoFormat='1.0')       

# Extract data for only the transmitter #138
T138 <- ExtractData(Vcrocs, 
                    sQueryTransmitterList = 138)

# Extract residence and non residence events using receiver data
# 	Minimum number of detections to register as a residence
# 	event = 2  
# 	Min time period between detections before residence event
# 	recorded = 43200 secs (12 hours)
T139Res <- RunResidenceExtraction(sInputFile=T138, 
                                 sLocation="RECEIVERID",
                                 iResidenceThreshold=2,
                                 iTimeThreshold=43200,
                                 sDistanceMatrix=NULL)

# The residences event table
T139resid <- T139Res$residences

# Generate the circuitous distance matrix
data(PointsCircuitous_crocs)
CircuitousDM <- GenerateCircuitousDistance(PointsCircuitous_crocs)

# Ensure there is only 1 Transmitter in dataset (if not, run the function within a loop)
length(unique(T139resid$TRANSMITTERID))

# Run the non-residence function
NonResidenceExtractId(sResidenceEventFile=T139resid,
                      sDistanceMatrix=CircuitousDM)