raster: blockSize – R documentation

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blockSize

Block size for writing files

Description

This function can be used to suggest chunk sizes (always a number of entire rows), and corresponding row numbers, to be used when processing Raster* objects in chunks. Normally used together with writeValues.

Usage

blockSize(x, chunksize, n=nlayers(x), minblocks=4, minrows=1)

Arguments

`x`	Raster* object
`chunksize`	Integer, normally missing. Can be used to set the block size; unit is number of cells. Block size is then computed in units of number of rows (always >= 1)
`n`	Integer. number of layers to consider. The function divides chunksize by n to determine blocksize
`minblocks`	Integer. Minimum number of blocks
`minrows`	Integer. Minimum number of rows in each block

Value

A list with three elements:

rows, the suggested row numbers at which to start the blocks for reading and writing,

nrows, the number of rows in each block, and,

n, the total number of blocks

Examples

r <- raster(system.file("external/test.grd", package="raster"))
blockSize(r)

raster

Geographic Data Analysis and Modeling

v3.4-10

GPL (>= 3)

Authors

Robert J. Hijmans [cre, aut] (<https://orcid.org/0000-0001-5872-2872>), Jacob van Etten [ctb], Michael Sumner [ctb], Joe Cheng [ctb], Dan Baston [ctb], Andrew Bevan [ctb], Roger Bivand [ctb], Lorenzo Busetto [ctb], Mort Canty [ctb], Ben Fasoli [ctb], David Forrest [ctb], Aniruddha Ghosh [ctb], Duncan Golicher [ctb], Josh Gray [ctb], Jonathan A. Greenberg [ctb], Paul Hiemstra [ctb], Kassel Hingee [ctb], Institute for Mathematics Applied Geosciences [cph], Charles Karney [ctb], Matteo Mattiuzzi [ctb], Steven Mosher [ctb], Babak Naimi [ctb], Jakub Nowosad [ctb], Edzer Pebesma [ctb], Oscar Perpinan Lamigueiro [ctb], Etienne B. Racine [ctb], Barry Rowlingson [ctb], Ashton Shortridge [ctb], Bill Venables [ctb], Rafael Wueest [ctb]

Initial release

2021-05-02