ch_wbt_pourpoints: Snap pour points to channels

In CSHS-hydRology/CSHShydRology: Canadian Hydrological Analyses

Snap pour points to channels

Description

Pour points describe the outlets of sub-basins within a DEM. To use the pour points to delineate catchments, they must align with the drainage network. This function snaps (forces the locations) of pour points to the channels.

Usage

ch_wbt_pourpoints(
  pp_sf = NULL,
  fn_flowacc,
  fn_pp,
  fn_pp_snap,
  check_crs = TRUE,
  snap_dist = NULL,
  ...
)

Arguments

pp_sf	sf object containing pour points. These must be supplied by the user. See the code in ch_volcano_pourpoints for an example of creating the object.
fn_flowacc	Name of file containing flow accumulations.
fn_pp	File name to create un-snapped pour points.
fn_pp_snap	File name for snapped pour points.
check_crs	If TRUE the projections of the pour points and flow accumulation files will be checked to ensure they are identical.
snap_dist	Maximum snap distance in map units.
...	Additional parameters for whitebox function wbt_snap_pour_points.

Value

Returns a sf object of the specified pour points snapped to the channel network.

Author(s)

Dan Moore

See Also

ch_volcano_pourpoints

Examples

# Not tested automatically as requires installation of Whitebox
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 accumulations
flow_acc_file <- tempfile("flow_acc", fileext = c(".tif"))
flow_acc <- ch_wbt_flow_accumulation(no_sink_raster_file, flow_acc_file)

# get pour points
pourpoint_file <- tempfile("volcano_pourpoints", fileext = c(".shp"))
pourpoints <- ch_volcano_pourpoints(pourpoint_file)
snapped_pourpoint_file <- tempfile("snapped_pourpoints", fileext = c(".shp"))
snapped_pourpoints <- ch_wbt_pourpoints(pourpoints, flow_acc_file, pourpoint_file,
snapped_pourpoint_file, snap_dist = 10)

CSHS-hydRology/CSHShydRology documentation built on Aug. 18, 2022, 4:44 p.m.