View source: R/apps_of_direction.R
riverdirection | R Documentation |
Calculates direction of travel between two points. Only works if river mouth (lowest point) has been specified (see setmouth).
riverdirection(
startseg,
endseg,
startvert,
endvert,
rivers,
flowconnected = FALSE,
stopiferror = TRUE,
algorithm = NULL
)
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 |
stopiferror |
Whether or not to exit with an error if a route cannot be
found. If this is set to |
algorithm |
Which route detection algorithm to use ( |
Direction: "up", "down", or "0" (character). Returns NA if flowconnected==TRUE
and the two segments are not flow-connected.
Building routes from the river mouth to each river network segment and/or distance lookup tables will greatly reduce computation time (see buildsegroutes).
Matt Tyers
setmouth
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)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.