compute_iFLO_weights {rdwplus}

Compute iFLO weights

Description

Compute an iFLO weight raster outside of the compute_metrics() function.

Usage

compute_iFLO_weights(
  pour_point,
  watershed,
  null_streams,
  flow_dir,
  out_flow_length,
  out_iFLO,
  out_iFLO_no_stream,
  idwp = -1,
  remove_streams = FALSE,
  ...
)

Arguments

pour_point

Pour point raster containing a single pour point (i.e., the outlet).

watershed

Watershed raster to use as a mask for the flow-path calculations.

null_streams

A streams raster with NoData for the stream cells and 1s everywhere else

flow_dir

A flow direction raster.

out_flow_length

Name of the output flow length raster.

out_iFLO

Name of the output weights raster.

out_iFLO_no_stream

Name of the output weights raster excluding cells on the stream line (ignored inf remove_streams = FALSE).

idwp

An inverse distance weighting power. This should be negative. The value idwp = -1 is the default.

remove_streams

A logical indicating whether cells corresponding to the stream line should be removed from the weights raster. Defaults to FALSE.

...

Optional extra arguments to get_flow_length().

Value

Nothing.

Examples

if(check_running()){
# Retrieve paths to data sets
dem <- system.file("extdata", "dem.tif", package = "rdwplus")
lus <- system.file("extdata", "landuse.tif", package = "rdwplus")
sts <- system.file("extdata", "site.shp", package = "rdwplus")
stm <- system.file("extdata", "streams.shp", package = "rdwplus")

# Set environment
set_envir(dem)

# Get other data sets (stream layer, sites, land use, etc.)
raster_to_mapset(lus)
vector_to_mapset(c(stm, sts))

# Reclassify streams
out_stream <- paste0(tempdir(), "/streams.tif")
rasterise_stream("streams", out_stream, TRUE)
reclassify_streams("streams.tif", "streams01.tif", overwrite = TRUE)

# Burn in the streams to the DEM
burn_in("dem.tif", "streams01.tif", "burndem.tif", overwrite = TRUE)

# Fill dem
fill_sinks("burndem.tif", "filldem.tif", "fd1.tif", "sinks.tif", overwrite = TRUE)

# Derive flow direction and accumulation grids
derive_flow("dem.tif", "fd.tif", "fa.tif", overwrite = T)

# Derive a new stream raster from the FA grid
derive_streams("dem.tif", "fa.tif", "new_stm.tif", "new_stm", min_acc = 200, overwrite = T)

# Recode streams
reclassify_streams("new_stm.tif", "null_stm.tif", "none")

# Snap sites to streams and flow accumulation
snap_sites("site", "new_stm.tif", "fa.tif", 2, "snapsite", T)

# Get watersheds
get_watersheds("snapsite", "fd.tif", "wshed.tif", T)

#  Get pour points
coord_to_raster("snapsite", which = 1, out = "pour_point")

# Get iFLO weights
compute_iFLO_weights(
"pour_point", 
"wshed.tif", 
"null_stm.tif", 
"fd.tif", 
"fl_outlet.tif", 
"iFLO_weights.tif", 
idwp = -1, 
remove_streams = FALSE
)
plot_GRASS("iFLO_weights.tif", col = topo.colors(12))
}