terra: init – R documentation

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init

Initialize a SpatRaster with values

Description

Create a SpatRaster with values reflecting a cell property: 'x', 'y', 'col', 'row', 'cell' or 'chess'. Alternatively, a function can be used. In that case, cell values are initialized without reference to pre-existing values. E.g., initialize with a random number (fun=runif). While there are more direct ways of achieving this for small objects (see examples) for which a vector with all values can be created in memory, the init function will also work for SpatRaster objects with many cells.

Usage

## S4 method for signature 'SpatRaster'
init(x, fun, filename="", ...)

Arguments

`x`	SpatRaster
`fun`	function to be applied. This must be a either single number, multiple numbers, a function, or one of a set of known character values. A function must take the number of cells as a single argument to return a vector of values with a length equal to the number of cells, such as `fun=runif`. Allowed character values are 'x', 'y', 'row', 'col', 'cell', and 'chess' to get the x or y coordinate, row, col or cell number or a chessboard pattern (alternating 0 and 1 values)
`filename`	character. Output filename
`...`	additional arguments for writing files as in `writeRaster`

Value

SpatRaster

Examples

r <- rast(ncol=10, nrow=5, xmin=0, xmax=10, ymin=0, ymax=5)
x <- init(r, fun="cell")
y <- init(r, fun=runif)

# initialize with a single value 
z <- init(r, fun=8)

terra

Spatial Data Analysis

v1.2-10

GPL (>= 3)

Authors

Robert J. Hijmans [cre, aut] (<https://orcid.org/0000-0001-5872-2872>), Roger Bivand [ctb] (<https://orcid.org/0000-0003-2392-6140>), Karl Forner [ctb], Jeroen Ooms [ctb] (<https://orcid.org/0000-0002-4035-0289>), Edzer Pebesma [ctb] (<https://orcid.org/0000-0001-8049-7069>)

Initial release

2021-05-12