get_DM: Navigate Downstream Mainstem
In nhdplusTools: NHDPlus Tools

get_DM

R Documentation

Navigate Downstream Mainstem

Description

Traverse NHDPlus network downstream main stem

Usage

get_DM(network, comid, distance = NULL, sort = FALSE, include = TRUE)

Arguments

`network`	data.frame NHDPlus flowlines including at a minimum: COMID, LENGTHKM, DnHydroseq, and Hydroseq.
`comid`	integer identifier to start navigating from.
`distance`	numeric distance in km to limit how many COMIDs are returned. The COMID that exceeds the distance specified is returned.
`sort`	if TRUE, the returned COMID vector will be sorted in order of distance from the input COMID (nearest to farthest)
`include`	if TRUE, the input COMID will be included in the returned COMID vector

Value

integer vector of all COMIDs downstream of the starting COMID along the mainstem

Examples

library(sf)

source(system.file("extdata", "sample_flines.R", package = "nhdplusTools"))

plot(sample_flines$geom)
start_COMID <- 11690092
DM_COMIDs <- get_DM(sample_flines, start_COMID)
plot(dplyr::filter(sample_flines, COMID %in% DM_COMIDs)$geom,
     col = "red", add = TRUE, lwd = 3)

DM_COMIDs <- get_DM(sample_flines, start_COMID, distance = 40)
plot(dplyr::filter(sample_flines, COMID %in% DM_COMIDs)$geom,
     col = "blue", add = TRUE, lwd = 2)

nhdplusTools documentation built on June 22, 2024, 10:36 a.m.