writeVector: Save a GVector to disk

In adamlilith/fasterRaster: Faster Raster and Spatial Vector Processing Using 'GRASS GIS'

Save a GVector to disk

Description

This function saves a GVector to disk directly from a GRASS session.

By default, files will be of OGC GeoPackage format (extension ".gpkg"), but this can be changed with the format argument. You can see a list of supported formats by simply using this function with no arguments, as in writeVector(), or by consulting the online help page for GRASS module v.out.ogr (see grassHelp("v.out.ogr")).

Note that if the vector has a data table attached and at least one numeric or integer column has an NA or NaN value, the function will yield a warning like:

Warning 1: Invalid value type found in record 2 for field column_with_NA_or_NaN. This warning will no longer be emitted.

Also note that despite the promise, this warning will be displayed again.

Usage

## S4 method for signature 'GVector,character'
writeVector(
  x,
  filename,
  overwrite = FALSE,
  format = NULL,
  attachTable = TRUE,
  ...
)

## S4 method for signature 'missing,missing'
writeVector(x, filename)

Arguments

x	A GVector.
filename	Character: Path and file name.
overwrite	Logical: If FALSE (default), do not save over existing files.
format	Character or NULL: File format. If NULL (default), then the function will attempt to get the format from the file name extension. Partial matching is used and case is ignored. You can see a list of formats using writeVector() (no arguments). Some common formats include: "GPKG": OGC GeoPackage (extension .gpkg). "CSV": Comma-separated value... saves the data table only, not the geometries (extension .csv). "ESRI Shapefile": ESRI shapefile (extension .shp). "GeoJSON": GeoJSON (extension GeoJSON) "KML": Keyhole Markup Language (extension .kml) "netCDF": NetCDF (extension .ncdf) "XLSX": MS Office Open XML spreadsheet (extension .xlsx).
attachTable	Logical: If TRUE (default), attach the attribute to table to the vector before saving it. If FALSE, the attribute table will not be attached.
...	Additional arguments to send to GRASS module v.out.ogr (see grassHelp("v.out.ogr")).

Value

Invisibly returns a GRaster (the input, x). Also saves the vector to disk.

See Also

terra::writeVector(), sf::st_write(), GRASS module v.out.ogr (see grassHelp("v.out.ogr"))

terra::writeVector(), the GRASS module manual page for v.out.ogr (see grassHelp("v.out.ogr"))

Examples

if (grassStarted()) {

# Setup
library(terra)

# Example data
madRivers <- fastData("madRivers")

# What file formats can we attempt to write?
writeVector()

# Convert SpatVector to GVector
rivers <- fast(madRivers)
rivers

# Save GVector to disk as GeoPackage
filename <- tempfile(fileext = ".gpkg")
writeVector(rivers, filename)

# Save GVector to disk as ESRI Shapefile
filename <- tempfile(fileext = ".shp")
writeVector(rivers, filename)

# Save GVector to disk as Google Earth KML
filename <- tempfile(fileext = ".klm")
writeVector(rivers, filename)

# Save GVector data table to disk as comma-separated file
filename <- tempfile(fileext = ".csv")
writeVector(rivers, filename)

# Save GVector data table to disk as NetCDF
filename <- tempfile(fileext = ".ncdf")
writeVector(rivers, filename)

# Save GVector data table to disk as Excel file
filename <- tempfile(fileext = ".xlsx")
writeVector(rivers, filename)

}

adamlilith/fasterRaster documentation built on Oct. 26, 2024, 4:06 p.m.