CSHShydRology (version 1.4.2)

ch_wbt_flow_direction: Creates flow direction grid file

Description

Creates flow direction grid file

Usage

ch_wbt_flow_direction(fn_dem_ns, fn_flowdir, return_raster = TRUE)

Value

If return_raster = TRUE (the default), the flow direction grid will be returned as a raster object, in addition to being written to fn_flowdir. If return_raster = FALSE, the output file will still be created but a NULL value is returned.

Arguments

fn_dem_ns

File name of dem with sinks removed.

fn_flowdir

File name for flow direction grid to be created.

return_raster

Should a raster object be returned?

Author

Dan Moore

Examples

# Only proceed if Whitebox executable is installed
library(whitebox)
if (check_whitebox_binary()){
  library(raster)
  test_raster <- ch_volcano_raster()
  dem_raster_file <- tempfile(fileext = c(".tif"))
  no_sink_raster_file <- tempfile("no_sinks", fileext = c(".tif"))

  # write test raster to file
  writeRaster(test_raster, dem_raster_file, format = "GTiff")

  # remove sinks
  removed_sinks <- ch_wbt_removesinks(dem_raster_file, no_sink_raster_file, method = "fill")

  # get flow directions
  flow_dir_file <- tempfile("flow_dir", fileext = c(".tif"))
  flow_dir <- ch_wbt_flow_direction(no_sink_raster_file, flow_dir_file)
  plot(flow_dir)
} else {
  message("Examples not run as Whitebox executable not found")
}