update: Update raster cells of files (on disk)

Description Usage Arguments Value Examples

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

1
2
3
4
## S4 method for signature 'RasterLayer'
update(object, v, cell, ...)
## S4 method for signature 'RasterBrick'
update(object, v, cell, band, ...)

Arguments

object

RasterLayer or RasterBrick that is associated with a file

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)

.

...

additional arguments. None implemented

Value

RasterLayer or RasterBrick

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
# 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)

raster documentation built on Nov. 17, 2017, 5:51 a.m.