Traverse NHDPlus network downstream main stem
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)
