riverdirectionseq {riverdist}

River Travel Direction Between Sequential Observations

Description

Returns a matrix of directions traveled by unique fish between sequential surveys. The mouth (lowest point) segment and vertex must be specified (see setmouth).

Usage

riverdirectionseq(
  unique,
  survey,
  seg,
  vert,
  rivers,
  logical = NULL,
  flowconnected = FALSE,
  stopiferror = TRUE,
  algorithm = NULL
)

Arguments

unique

A vector of identifiers for each fish.

survey

A vector of identifiers for each survey. It is recommended to use a numeric or date format (see as.Date) to preserve survey order.

seg

A vector of river locations (segment component).

vert

A vector of river locations (vertex component).

rivers

The river network object to use.

logical

A boolean vector that can be used for subsetting - if used, riverdirectionseq() will only return pairwise distances in which a specified condition is met.

flowconnected

If TRUE, only returns direction if the 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.

Value

A data frame of directions (character), with rows defined by unique fish and columns defined by observation increment (1 to 2, 2 to 3, etc.) See riverdirection for additional information.

Note

Building routes from the river mouth to each river network segment and/or distance lookup tables will greatly reduce computation time (see buildsegroutes).

Author(s)

Matt Tyers

See Also

riverdirection

Examples

data(Gulk, fakefish)

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

riverdirectionseq(unique=fakefish$fish.id, survey=fakefish$flight, seg=fakefish$seg,
   vert=fakefish$vert, rivers=Gulk)

riverdirectionseq(unique=fakefish$fish.id, survey=fakefish$flight.date, seg=fakefish$seg,
   vert=fakefish$vert, rivers=Gulk)