nhdplusTools (version 0.3.8)

calculate_levelpaths: Calculate Level Paths

Description

Calculates level paths using the stream-leveling approach of NHD and NHDPlus. In addition to a levelpath identifier, a topological sort and levelpath outlet identifier is provided in output. If arbolate sum is provided in the weight column, this will match the behavior of NHDPlus. Any numeric value can be included in this column and the largest value will be followed when no nameID is available.

Usage

calculate_levelpaths(flowline, status = FALSE)

Arguments

flowline

data.frame with ID, toID, nameID, and weight columns.

status

boolean if status updates should be printed.

Value

data.frame with ID, outletID, topo_sort, and levelpath collumns. See details for more info.

Details

1. levelpath provides an identifier for the collection of flowlines that make up the single mainstem flowpath of a total upstream aggregate catchment.

2. outletID is the catchment ID (COMID in the case of NHDPlus) for the catchment at the outlet of the levelpath the catchment is part of.

3. topo_sort is similar to Hydroseq in NHDPlus in that large topo_sort values are upstream of small topo_sort values. Note that there are many valid topological sort orders of a directed graph. The sort order output by this function is generated using `igraph::topo_sort`.

Examples

# NOT RUN {
source(system.file("extdata", "walker_data.R", package = "nhdplusTools"))

test_flowline <- prepare_nhdplus(walker_flowline, 0, 0, FALSE)

test_flowline <- data.frame(
  ID = test_flowline$COMID,
  toID = test_flowline$toCOMID,
  nameID = walker_flowline$GNIS_ID,
  weight = walker_flowline$ArbolateSu,
  stringsAsFactors = FALSE)

calculate_levelpaths(test_flowline)


# }