VTrack (version 1.10)

GenerateCircuitousDistance: Converts a Points File into a Distance Matrix Using the Circuitous Distances Along a Series of Receivers or Stations

Description

This function calculates the straight line distance beween a set of geographical coordinates and generates a matrix containing the distances between each of the locations (i.e. receivers/stations) minus the detection radius. This function works in series through a set of locations and may contain waypoints to create indirect paths.

Usage

GenerateCircuitousDistance(sPointsFile)

Arguments

sPointsFile

a dataframe containing the LOCATION (i.e. the STATIONNAME or the RECEIVERID), the coordinates and the detection RADIUS in meters. This should be in the format LOCATION, LATITUDE, LONGITUDE,

Value

• DM
  a 2x2 matrix containing the pairwise circuitous DISTANCE between each LOCATION minus the detection RADIUS. Distances are returned in kilometers

See Also

GenerateDirectDistance

Examples

# Load the points file
data(PointsCircuitous_crocs)

# Generate the Circuitous Distance Matrix
CircuitousDM <- GenerateCircuitousDistance(PointsCircuitous_crocs)

# Now plot example of how circuitous distances between receivers were generated
# In this example an individual must follow the course of the river in order to
#   move between receivers
par(mfrow=c(1,1),las=1,bty="l")
plot(PointsCircuitous_crocs$LONGITUDE,PointsCircuitous_crocs$LATITUDE,
    pch=1,cex=0.5,col="grey",xlab="Longitude",ylab="Latitude")
lines(PointsCircuitous_crocs$LONGITUDE,PointsCircuitous_crocs$LATITUDE,
      col="grey",lwd=0.3,lty=3)

Receiversonly <- na.omit(PointsCircuitous_crocs)
points(Receiversonly$LONGITUDE,Receiversonly$LATITUDE,pch=10,cex=1)