createStreams {SAiVE}

Create stream network from DEM

Description

Creates a stream network from a provided DEM. In most cases it is advisable to first hydro-process the DEM (see hydroProcess()) to remove depressions which preclude continuous flow from one DEM cell to the next.

Usage

createStreams(
  DEM,
  threshold,
  vector = NULL,
  save_path = NULL,
  n.cores = NULL,
  force_update_wbt = FALSE,
  silent_wbt = TRUE
)

Arguments

DEM

The path to a digital elevation model file with .tif extension, or a terra spatRaster object. It is usually advisable to have already hydro-processed the DEM to remove artificial depressions. See hydroProcess().

threshold

The accumulation threshold in DEM cells necessary to start defining a stream.

vector

Output file specifications. NULL for no vector file at all; "env" for only a variable returned to the R environment; or, to return to environment and save to disk, "gpkg" for a geopackage file, "shp" for a shapefile.

save_path

An optional path in which to save the newly created stream network. If left NULL will save it in the same directory as the provided DEM or, if the DEM is a terra object, return only terra objects.

n.cores

The maximum number of cores to use. Leave NULL to use all cores minus 1.

force_update_wbt

Whitebox Tools is by default only downloaded if it cannot be found on the computer, and no check are performed to ensure the local version is current. Set to TRUE if you know that there is a new version and you would like to use it.

silent_wbt

Should Whitebox tools messages be suppressed? This function prints messages to the console already but these messages can be useful if you need to do some debugging.

Details

This function is essentially a convenient wrapper around three WhiteboxTools geospatial tools (whitebox::wbt_d8_flow_accumulation(), whitebox::wbt_d8_pointer(), and whitebox::wbt_extract_streams()) and some terra functions to convert rasters to vector files.

Value

A raster representation of streams and, if requested, a vector representation of streams. Returned as terra objects and saved to disk if save_path is not null.

Author(s)

Ghislain de Laplante ([e-mail] or [e-mail])

Examples

hydroDEM <- hydroProcess(elev, 200, streams, n.cores = 2)
res <- createStreams(hydroDEM, 50, n.cores = 2)

terra::plot(res$streams_derived)