openSTARS (version 1.2.2)

restrict_network: Restrict edges to certain stream networks

Description

When the stream network is derived from a DEM, the network will cover the whole extent of the DEM input. However, the observation sites might be restricted to a certain area, i.e. to certain networks. This function deletes edges that belong to networks (based on their netID) without sites (observation or prediction). This can help to save computation time before calculating edge attributes.

Usage

restrict_network(
  sites = NULL,
  keep_netIDs = NULL,
  delete_netIDs = NULL,
  keep = TRUE,
  filename = "edges_o"
)

Arguments

sites

name(s) of sites.

keep_netIDs

numeric (optional); vector of netIDs to keep

delete_netIDs

numeric (optional); vector of netIDs to delete

keep

boolean; should the original 'edges' be saved? Default is TRUE.

filename

character string; file name to save the original edges vector file; defaults to 'edges_o'.

Value

Nothing. The function updates 'edges' and (if keep = TRUE) saves the original file to the file name provided.

Examples

# NOT RUN {
dem_path <- system.file("extdata", "nc", "elev_ned_30m.tif", package = "openSTARS")
if(.Platform$OS.type == "windows"){
  grass_program_path = "c:/Program Files/GRASS GIS 7.6"
  } else {
  grass_program_path = "/usr/lib/grass78/"
  }

setup_grass_environment(dem = dem_path, 
                        gisBase = grass_program_path,      
                        remove_GISRC = TRUE,
                        override = TRUE
                        )
gmeta()

# Load files into GRASS
dem_path <- system.file("extdata", "nc", "elev_ned_30m.tif", package = "openSTARS")
sites_path <- system.file("extdata", "nc", "sites_nc.shp", package = "openSTARS")
lakes_path <- system.file("extdata", "nc", "lakes.shp", package = "openSTARS")
import_data(dem = dem_path, sites = sites_path)

# Derive streams from DEM
derive_streams(burn = 0, accum_threshold = 100, condition = TRUE, clean = TRUE)

# Check and correct complex confluences (there are no complex confluences in this
# example date set; set accum_threshold in derive_streams to a smaller value
# to create complex confluences)
cj <- check_compl_confluences()
if(cj){
  correct_compl_confluences()
}

calc_edges()
calc_sites()
restrict_network(sites = "sites", keep = TRUE, filename = "edges_o")

# plot
library(sp)
edges <- readVECT('edges', ignore.stderr = TRUE)
edges_o <- readVECT('edges_o', ignore.stderr = TRUE)
sites <- readVECT('sites', ignore.stderr = TRUE)
plot(edges_o, col = "lightblue", lwd = 2)
lines(edges, col = "blue4", lty = 2) 
points(sites, pch = 16, col = "red")
legend("topright", col = c("red", "lightblue", "blue4"), lty = c(NA, 1, 2),
       lwd = c(NA,2,1), pch = c(16,NA,NA),
       legend = c("sites", "edges original", "edges restricted"))
# }