export_ssn: Export 'SSN' object

In openSTARS: An Open Source Implementation of the 'ArcGIS' Toolbox 'STARS'

Description

This function exports the calculated sites, edges and binary IDs to a folder which then can be read using the 'SSN' package.

Usage

export_ssn(path, predictions = NULL, delete_directory = FALSE)

Arguments

path	character; path to write .ssn object to.
predictions	name(s) of prediction map(s) (optional).
delete_directory	boolean; shall the ssn directory and all files be deleted before export in case it already exists? See details.

Details

First it is checked if one of the column names is longer than 10 characters (which cannot be exported to ESRI shape files as required by 'SSN').

delete_directory = TRUE is useful if the same directory name has been used before and the existing data shall be overwritten.

Value

Nothing. Files are written to the specified folder

Author(s)

Mira Kattwinkel,[e-mail], Eduard Szoecs, [e-mail]

Examples

dem_path <- system.file("extdata", "nc", "elev_ned_30m.tif", package = "openSTARS")
if(.Platform$OS.type == "windows"){
  grass_program_path = "c:/Program Files/GRASS GIS 7.6"
  } else {
  grass_program_path = "/usr/lib/grass78/"
  }

setup_grass_environment(dem = dem_path, 
                        gisBase = grass_program_path,      
                        remove_GISRC = TRUE,
                        override = TRUE
                        )
gmeta()
                        
# Load files into GRASS
dem_path <- system.file("extdata", "nc", "elev_ned_30m.tif", package = "openSTARS")
sites_path <- system.file("extdata", "nc", "sites_nc.shp", package = "openSTARS")
import_data(dem = dem_path, sites = sites_path)

# Derive streams from DEM
derive_streams(burn = 0, accum_threshold = 700, condition = TRUE, clean = TRUE)

# Check and correct complex confluences (there are no complex confluences in this
# example date set; set accum_threshold in derive_streams to a smaller value
# to create complex confluences)
cj <- check_compl_confluences()
if(cj){
  correct_compl_confluences()
}

# Prepare edges
calc_edges()

# Prepare site
calc_sites()

# Write data to SSN Folder
ssn_dir <- file.path(tempdir(), 'nc.ssn')
export_ssn(ssn_dir, delete_directory = TRUE)
list.files(ssn_dir)

openSTARS documentation built on Feb. 4, 2022, 5:08 p.m.