calc_edges | R Documentation |
A vector (lines) map 'edges' is derived from 'streams_v' and several attributes are assigned.
calc_edges()
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
# 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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