Description Usage Details Value Note Author(s) Examples
A vector (lines) map 'edges' is derived from 'streams_v' and several attributes are assigned.
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Steps include:
Assign unique 'rid' to each stream segment
Find different stream networks in the region and assign 'netID'
Calculate segments upstream distance, 'upDist' = flow length from the upstream node of the stream segment to the outlet of the network
Calculate reach contributing areas (RCA ) per segment, 'rcaArea' = subcatchment area of each segment in square km
Calculate catchment areas, 'H2OArea' = total catchment area of each segment in square km
All lengths are rounded to 2 and all areas to 6 decimal places, respectively.
Nothing. The function produces the following map:
'edges': derived stream segments with computed attributes needed for 'SSN' (vector)
setup_grass_environment
, import_data
and
derive_streams
must be run before.
Mira Kattwinkel, mira.kattwinkel@gmx.net, Eduard Szoecs, eduardszoecs@gmail.com
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | # Initiate and setup GRASS
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")
import_data(dem = dem_path, sites = sites_path)
# Derive streams from DEM
derive_streams(burn = 0, accum_threshold = 700, condition = TRUE, clean = TRUE)
check_compl_confluences()
# Prepare edges
calc_edges()
# Plot data
library(sp)
dem <- readRAST('dem', ignore.stderr = TRUE, plugin = FALSE)
edges <- readVECT('edges', ignore.stderr = TRUE)
plot(dem, col = terrain.colors(20))
lines(edges, col = 'blue')
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