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General mathematical methods

math-generics.Rd

Standard mathematical methods for computations with SpatRasters. Computations are local (applied on a cell by cell basis). If multiple SpatRasters 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 class 'SpatRaster'
sqrt(x)

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

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

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

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

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

See also

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

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

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")
#> class       : SpatRaster 
#> size        : 10, 10, 2  (nrow, ncol, nlyr)
#> resolution  : 36, 18  (x, y)
#> extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84) 
#> source(s)   : memory
#> names       :     lyr.1, lyr.1 
#> min values  : 0.1272139,   0.1 
#> max values  : 0.9963790,   1.0 

round(s, 1)
#> class       : SpatRaster 
#> size        : 10, 10, 2  (nrow, ncol, nlyr)
#> resolution  : 36, 18  (x, y)
#> extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84) 
#> source(s)   : memory
#> names       : lyr.1, lyr.1 
#> min values  :   0.1,   0.1 
#> max values  :   1.0,   1.0 

cumsum(r)
#> class       : SpatRaster 
#> size        : 10, 10, 2  (nrow, ncol, nlyr)
#> resolution  : 36, 18  (x, y)
#> extent      : -180, 180, -90, 90  (xmin, xmax, ymin, ymax)
#> coord. ref. : lon/lat WGS 84 (CRS84) (OGC:CRS84) 
#> source(s)   : memory
#> names       :      lyr.1,      lyr.1 
#> min values  : 0.01618339, 0.02618339 
#> max values  : 0.99277109, 1.84138276