rdwplus (version 0.1.0)

derive_streams: Extract streams from a flow accumulation raster

Description

Derive a set of stream lines from a flow accumulation raster.

Usage

derive_streams(
  dem,
  flow_acc,
  out,
  min_acc = 1000,
  min_length = 0,
  overwrite = FALSE,
  ...
)

Value

Nothing. A vector dataset with the name basename(out) will appear in the current GRASS mapset.

Arguments

dem

Name of the elevation raster in the current GRASS mapset.

flow_acc

Name of the flow accumulation raster in the current GRASS mapset.

out

File path to the output vector dataset of stream lines. Should be WITHOUT .shp extension.

min_acc

The minimum accumulation value (in upstream cells) that a cell needs to have in order to be classified as a stream. Defaults to 1000.

min_length

The minimum length of a stream segment in cells. Defaults to 0.

overwrite

A logical indicating whether the output should be allowed to overwrite existing files. Defaults to FALSE.

...

Additional arguments to r.stream.extract.

Examples

 
# Will only run if GRASS is running
if(check_running()){

# Load data set
dem <- system.file("extdata", "dem.tif", package = "rdwplus")
stream_shp <- system.file("extdata", "streams.shp", package = "rdwplus")

# Set environment parameters
set_envir(dem)

# Set 
raster_to_mapset(rasters = c(dem), as_integer = c(FALSE))
vector_to_mapset(vectors = c(stream_shp))

# Create binary stream
rasterise_stream("streams", "streams_rast.tif", overwrite = TRUE)
reclassify_streams("streams_rast.tif", "streams_binary.tif",
 out_type = "binary", overwrite = TRUE)

# Burn dem 
burn_in(dem = "dem.tif", stream = "streams_binary.tif", 
out = "dem_burn.tif", burn = 10, overwrite = TRUE)

# Fill sinks
fill_sinks(dem = "dem_burn.tif", out = "dem_fill.tif", size = 1, overwrite = TRUE)

# Derive flow accumulation and direction grids
derive_flow(dem = "dem_fill.tif", flow_dir = "fdir.tif",  
flow_acc = "facc.tif", overwrite = TRUE)

# Derive streams 
derive_streams(dem = "dem_fill.tif", flow_acc = "facc.tif", out = "stream_lines", overwrite = TRUE)
}