limit: Limit range of values in a 'SpatRaster' object

In rampage: Calibrated Color Ramps

Limit range of values in a SpatRaster object

Description

Shorthand for limiting maximum and minimum values in a SpatRaster-class object.

Usage

limit(x, y = NULL, min = NULL, max = NULL)

Arguments

x	Object to limit, a SpatRaster-class object.
y	Either a range (i.e. a numeric vector with two values), or data.frame with positioned color values (column z indicates values), or a calibrated ramp (e.g. produced with expand).
min	If y is not given, the minimum value to have in the data.frame.
max	If y is not given, the maximum value to have in the data.frame.

Value

A SpatRaster object.

Examples

# This function relies on the terra extension
if(requireNamespace("terra", quietly=TRUE)){
 library(terra)
	# Example 1. Using specific values
	# a SpatRaster object
	r<- terra::rast()
	# populate with a Gaussian distribution
	terra::values(r) <- rnorm(terra::ncell(r), 0.5,1 )
	# and limit
	rLimit <- limit(r, min=-0.2, max=0.2)
	plot(rLimit)


	# Example 2. Using an expanded color ramp
	# Create a data.frame
	df <- data.frame(
		z=c(-1, -0.2, 0, 0.2, 1),
		color=rev(gradinv(5))
	)
	ramp <- expand(df, n=200)
	rLimited <- limit(r, y=ramp)
	# default
	plot(rLimited)

	# manual ramping.
	plot(rLimited, breaks=ramp$breaks, col=ramp$col,
		legend=FALSE)

	# temporary solution for manual legend
	# Marginal ramps will be implemented later
	ramplegend(x=140, y=90, ramp=ramp, cex=0.5,
		at=c(-1, 0, 1), label=c("< -1", 0, "> +1"))


}

rampage documentation built on Aug. 8, 2025, 7:38 p.m.