Contour lines from a "GRaster"

Create a GVector of contour lines from a GRaster.

Usage

# S4 method for class 'GRaster'
as.contour(x, nlevels, levels)

Arguments

x

A GRaster.

nlevels

Numeric: A positive integer or missing (default). Number of levels at which to calculate contours. Levels will be calculated in equal-sized steps from the smallest to the largest value of x. Either nlevels or levels must be specified.

levels

Numeric vector: A numeric vector of values at which to calculate contour lines. Either nlevels or levels must be specified.

Value

A GVector representing contour lines.

See also

terra::as.contour(), GRASS manual page for module r.contour (see grassHelp("r.contour"))

Examples

if (grassStarted()) {

# Setup
library(terra)

# Elevation raster
madElev <- fastData("madElev")

# Convert a SpatRaster to a GRaster:
elev <- fast(madElev)

# Calculate contour lines:
conts <- as.contour(elev, nlevels = 10)

plot(elev)
plot(conts, add = TRUE)

}