riverdirection: River Direction

Description

Calculates direction of travel between two points. Only works if river mouth (lowest point) has been specified (see setmouth).

Usage

riverdirection(
  startseg,
  endseg,
  startvert,
  endvert,
  rivers,
  flowconnected = FALSE,
  stopiferror = TRUE,
  algorithm = NULL
)

Value

Direction: "up", "down", or "0" (character). Returns NA if flowconnected==TRUE and the two segments are not flow-connected.

Arguments

startseg: Segment number of the start of the route
endseg: Segment number of the end of the route
startvert: Vertex number of the start of the route
endvert: Vertex number of the end of the route
rivers: The river network object to use
flowconnected: If TRUE, only returns direction if the two input segments are flow-connected. Defaults to FALSE.
stopiferror: Whether or not to exit with an error if a route cannot be found. If this is set to FALSE and a route cannot be found, the function will return NA in the appropriate entry. Defaults to TRUE. See detectroute.
algorithm: Which route detection algorithm to use ("Dijkstra", "sequential", or "segroutes"). If left as NULL (the default), the function will automatically make a selection. See detectroute for more details.

Author

Matt Tyers

Examples

Run this code

data(Gulk)

# Mouth must be specified
Gulk$mouth$mouth.seg <- 1
Gulk$mouth$mouth.vert <- 1

plot(x=Gulk)
riverdirection(startseg=6, endseg=3, startvert=40, endvert=40, rivers=Gulk)