math-generics: General mathematical methods

In terra: Spatial Data Analysis

General mathematical methods

Description

Standard mathematical methods for computations with SpatRaster objects. Computations are local (applied on a cell by cell basis). If multiple SpatRaster objects are used, these must have the same extent and resolution. These have been implemented:

abs, sign, sqrt, ceiling, floor, trunc, cummax, cummin, cumprod, cumsum, log, log10, log2, log1p, acos, acosh, asin, asinh, atan, atanh, exp, expm1, cos, cosh, sin, sinh, tan, tanh, round, signif

Instead of directly calling these methods, you can also provide their name to the math method. This is useful if you want to provide an output filename.

The following methods have been implemented for SpatExtent: round, floor, ceiling

round has also been implemented for SpatVector, to round the coordinates of the geometries.

Usage

## S4 method for signature 'SpatRaster'
sqrt(x)

## S4 method for signature 'SpatRaster'
log(x, base=exp(1))

## S4 method for signature 'SpatRaster'
round(x, digits=0)

## S4 method for signature 'SpatRaster'
math(x, fun, digits=0, filename="", overwrite=FALSE, ...)

## S4 method for signature 'SpatVector'
round(x, digits=4)

## S4 method for signature 'SpatRaster'
cumsum(x)

Arguments

x	SpatRaster
base	a positive or complex number: the base with respect to which logarithms are computed
digits	Number of digits for rounding
fun	character. Math function name
filename	character. Output filename
overwrite	logical. If TRUE, filename is overwritten
...	additional arguments for writing files as in writeRaster

Value

SpatRaster or SpatExtent

See Also

See app to use mathematical functions not implemented by the package, and Arith-methods for arithmetical operations. Use roll for rolling functions.

Examples

r1 <- rast(ncols=10, nrows=10)
v <- runif(ncell(r1))
v[10:20] <- NA
values(r1) <- v
r2 <- rast(r1)
values(r2) <- 1:ncell(r2) / ncell(r2)
r <- c(r1, r2)

s <- sqrt(r)
# same as 
math(r, "sqrt")

round(s, 1)

cumsum(r)

terra documentation built on Oct. 13, 2023, 5:08 p.m.