get_streamlevel: Get Streamlevel

View source: R/get_codes.R

get_streamlevelR Documentation

Get Streamlevel


Applies a topological sort and calculates stream level. Algorithm: Terminal level paths are assigned level 1 (see note 1). Paths that terminate at a level 1 are assigned level 2. This pattern is repeated until no paths remain.

If a TRUE/FALSE coastal attribute is included, coastal terminal paths begin at 1 and internal terminal paths begin at 4 as is implemented by the NHD stream leveling rules.





data.frame with levelpathi, dnlevelpat, and optionally a coastal flag. If no coastal flag is included, all terminal paths are assumed to be coastal.


numeric stream order in same order as input


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

test_flowline <- data.frame(
 levelpathi = walker_flowline$LevelPathI,
 dnlevelpat = walker_flowline$DnLevelPat)

 test_flowline$dnlevelpat[1] <- 0

(level <- get_streamlevel(test_flowline))

walker_flowline$level <- level

plot(sf::st_geometry(walker_flowline), lwd = walker_flowline$level, col = "blue")

test_flowline$coastal <- rep(FALSE, nrow(test_flowline))
(level <- get_streamlevel(test_flowline))

test_flowline$coastal[!test_flowline$dnlevelpat %in% test_flowline$levelpathi] <- TRUE
(level <- get_streamlevel(test_flowline))

nhdplusTools documentation built on Oct. 2, 2023, 5:06 p.m.