nhdR (version 0.5.3)

extract_network: Return nhd plus stream network upstream of a waterbody

Description

Return nhd plus stream network upstream of a waterbody

Usage

extract_network(
  lon = NA,
  lat = NA,
  lines = NA,
  buffer_dist = 0.01,
  maxsteps = 3,
  approve_all_dl = FALSE,
  ...
)

Arguments

lon

numeric decimal degree longitude

lat

numeric decimal degree latitude

lines

sf spatial lines object to limit the extent of the network search

buffer_dist

numeric buffer around lat-lon point in dec. deg.

maxsteps

maximum number of stream climbing iterations

approve_all_dl

logical blanket approval to download all missing data. Defaults to TRUE if session is non-interactive.

...

parameters passed on to sf::st_read

Details

The lon and lat arguments are used for querying the corresponding lake polygon layer which is then used to climb its intersecting stream network.

Examples

# NOT RUN {
library(mapview)
library(sf)

# headwater lakes have no upstream network
coords <- data.frame(lat = 46.32711, lon = -89.58893)
res <- extract_network(coords$lon, coords$lat, maxsteps = 9)

# fails if no lake nhdp lake found within the buffer at the query point
coords <- data.frame(lat = 43.62453, lon = -85.47164)
res <- extract_network(coords$lon, coords$lat, maxsteps = 9)

coords <- data.frame(lat = 20.79722, lon = -156.47833)
# use a non-geographic (projected) buffer size
res <- extract_network(coords$lon, coords$lat, maxsteps = 9,
        buffer_dist = units::as_units(5, "km"))

# use a projected buffer size
res <- extract_network(coords$lon, coords$lat, maxsteps = 9)

# no upstream network for lakes intersecting the Great Lakes
coords <- data.frame(lat = 44.6265, lon = -86.23121)
res <- extract_network(coords$lon, coords$lat, maxsteps = 3)

coords <- data.frame(lat = 42.96523, lon = -89.2527)
res <- extract_network(coords$lon, coords$lat, maxsteps = 9)

mapview(res)

# }

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