VTrack (version 1.11)

ReturnVR2Distance: Extract the Distances Moved Between VR2 Receiver Units Within the Acoustic Detection Database

Description

This function uses combines the non-residence event table with a distance matrix to extract the minimum distance moved between two receivers. This function returns a numeric vector containing the minimum distance moved between receivers (extracted from 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

ReturnVR2Distance(NonResidenceFile, sDistanceMatrix)

Arguments

NonResidenceFile

a data frame containing the nonresidences event table

sDistanceMatrix

a two dimentional array (matrix) containing the pairwise distances between an array of VR2 receivers

Value

a numeric vector of minimum distance travelled (in kilometers) corresponding to the values listed in the distance matrix

See Also

RunResidenceExtraction, NonResidenceExtractId

Examples

## Not run: 
# # Extract residence events at RECEIVERS from the VTrack transformed 
# #   crocodile dataset
# 
# # Load the crocodile dataset into the VTrack archive format
# 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
# #   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 nonresidences event table
# T139nonresid <- T139Res$nonresidences
# 
# # Generate the Direct Distance Matrix
# data(PointsDirect_crocs)
# DirectDM <- GenerateDirectDistance(PointsDirect_crocs)
# 
# # Run the VR2 distances function
# (My_distances <- ReturnVR2Distance(NonResidenceFile = T139nonresid,
#                                    sDistanceMatrix = DirectDM))
# ## End(Not run)