R: Mask values in a Raster object

mask {raster} | R Documentation

## Mask values in a Raster object

### Description

Create a new Raster* object that has the same values as `x`, except for the cells that are `NA` (or other `maskvalue`) in a 'mask'. These cells become `NA` (or other `updatevalue`). The mask can be either another Raster* object of the same extent and resolution, or a Spatial* object (e.g. SpatialPolygons) in which case all cells that are not covered by the Spatial object are set to `updatevalue`. You can use `inverse=TRUE` to set the cells that are not `NA` (or other `maskvalue`) in the mask, or not covered by the Spatial* object, to `NA` (or other `updatvalue`).

### Usage

    ## S4 method for signature 'RasterLayer,RasterLayer'
    mask(x, mask, filename="", inverse=FALSE,
          maskvalue=NA, updatevalue=NA, updateNA=FALSE, ...)

    ## S4 method for signature 'RasterStackBrick,RasterLayer'
    mask(x, mask, filename="", inverse=FALSE,
          maskvalue=NA, updatevalue=NA, updateNA=FALSE, ...)

    ## S4 method for signature 'RasterLayer,RasterStackBrick'
    mask(x, mask, filename="", inverse=FALSE,
          maskvalue=NA, updatevalue=NA, updateNA=FALSE, ...)

    ## S4 method for signature 'RasterStackBrick,RasterStackBrick'
    mask(x, mask, filename="", inverse=FALSE,
          maskvalue=NA, updatevalue=NA, updateNA=FALSE, ...)

    ## S4 method for signature 'Raster,Spatial'
    mask(x, mask, filename="", inverse=FALSE,
          updatevalue=NA, updateNA=FALSE, ...)

### Arguments

`x` | Raster* object
`mask` | Raster* object or a Spatial* object
`filename` | character. Optional output filename
`inverse` | logical. If `TRUE`, areas on mask that are _not_ the `maskvalue` are masked
`maskvalue` | numeric. The value in `mask` that indicates the cells of `x` that should become `updatevalue` (default = `NA`)
`updatevalue` | numeric. The value that cells of `x` should become if they are not covered by `mask` (and not `NA`)
`updateNA` | logical. If `TRUE`, `NA` values outside the masked area are also updated to the the `updatevalue` (only relevant if the `updatevalue` is not `NA`
`...` | additional arguments as in `writeRaster`

### Value

Raster* object

### See Also

`rasterize, crop`

### Examples

    r <- raster(ncol=10, nrow=10)
    m <- raster(ncol=10, nrow=10)
    values(r) <- runif(ncell(r)) * 10
    values(m) <- runif(ncell(r))
    m[m < 0.5] <- NA
    mr <- mask(r, m)

    m2 <- m > .7
    mr2 <- mask(r, m2, maskvalue=TRUE)

[Package raster version 3.3-7 Index]