rasterize: Convert a GVector to a GRaster

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

Convert a GVector to a GRaster

Description

The rasterize() function converts a GVector into a GRaster.

Usage

## S4 method for signature 'GVector,GRaster'
rasterize(x, y, field = "", background = NA, by = NULL, verbose = TRUE)

Arguments

x	A GVector.
y	A GRaster: The new raster will have the same extent and resolution as this raster.
field	Character: Name of a column in the data table of y to "burn" into the raster. If not "" (default), then the output will be a categorical GRraster. If field is "", then all geometries will be "burned" to the raster and have the same value.
background	Numeric or NA (default): Value to put in cells that are not covered by the GVector. Note that if this is not NA and not an integer, then the output cannot be a categorical raster (i.e., there will be no "levels" table associated with it).
by	Either NULL (default) or character: If this is not NULL, then the GVector will be subset by the values in the field named by by. The output will be a multi-layer raster, with one layer per unique value in by.
verbose	Logical: If by is not NULL, display progress.

Value

A GRaster.

See Also

terra::rasterize(), GRASS module v.to.rast (see grassHelp("v.to.rast"))

Examples

if (grassStarted()) {

# Setup
library(sf)
library(terra)

# Elevation raster, outline of a part of Madagascar, and rivers vector:
madElev <- fastData("madElev") # raster
madDypsis <- fastData("madDypsis") # points vector
madRivers <- fastData("madRivers") # lines vector
madCoast4 <- fastData("madCoast4") # polygons vector

# Convert to GRaster and GVectors:
elev <- fast(madElev)
dypsis <- fast(madDypsis)
coast4 <- fast(madCoast4)
rivers <- fast(madRivers)

# Convert points, line, and polygons vectors to rasters:
points <- rasterize(dypsis, elev)
plot(points)

lines <- rasterize(rivers, elev)
plot(lines)

polys <- rasterize(coast4, elev)
plot(polys)

communes <- rasterize(coast4, elev, field = "NAME_4")
plot(communes)

# Change background value:
polysNeg1 <- rasterize(coast4, elev, background = -1)
plot(polysNeg1)

# Make one layer per river:
byRiver <- rasterize(rivers, elev, field = "NAM", by = "NAM")
plot(byRiver)

}

adamlilith/fasterRaster documentation built on Dec. 21, 2024, 2:04 a.m.