raster (version 2.5-8)

update: Update raster cells of files (on disk)

Description

Update cell values of a file (i.e., cell values on disk) associated with a RasterLayer or RasterBrick.

User beware: this function _will_ make changes to your file (first make a copy if you are not sure what you are doing).

Writing starts at a cell number cell. You can write a vector of values (in cell order), or a matrix. You can also provide a vector of cell numbers (of the same length as vector v) to update individual cells.

See writeFormats for supported formats.

Usage

update(object, ...)

Arguments

object

RasterLayer or RasterBrick that is associated with a file

...

Additional arguments.

v - vector or matrix with new values

cell - cell from where to start writing. Or a vector of cell numbers if v is a vector of the same length.

band - band (layer) to update (for RasterBrick objects).

Value

RasterLayer or RasterBrick

Examples

# NOT RUN {
# setting up an example RasterLayer with file
r <- raster(nrow=5, ncol=10)
r[] = 0
r <- writeRaster(r, 'test', overwrite=TRUE, datatype='INT2S')
as.matrix(r)

# update with a vector starting a cell
r <- update(r, v=rep(1, 5), cell=6)
# 99.99 gets rounded because this is an integer file
r <- update(r, v=9.99, cell=50)
as.matrix(r)

# update with a vector of values and matching vector of cell numbers
r <- update(r, v=5:1, cell=c(5,15,25,35,45))
as.matrix(r)

# updating with a marix, anchored at a cell number
m = matrix(1:10, ncol=2)
r <- update(r, v=m, cell=2)
as.matrix(r)
# }