# which

From raster v2.9-5
by Robert Hijmans

##### Which cells are TRUE?

`Which`

returns a RasterLayer with `TRUE`

or `FALSE`

setting cells that are `NA`

to `FALSE`

(unless `na.rm=FALSE`

). If the RasterLayer has numbers, all values that are 0 become `FALSE`

and all other values become `TRUE`

. The function can also return the cell numbers that are `TRUE`

- Keywords
- spatial

##### Usage

```
# S4 method for RasterLayer
Which(x, cells=FALSE, na.rm=TRUE, ...)
```

##### Arguments

- x
RasterLayer

- cells
logical. If

`TRUE`

, cell numbers are returned, otherwise a RasterLayer is returned- na.rm
logical. If

`TRUE`

,`NA`

values are treated as`FALSE`

, otherwise they remain`NA`

(only when`cells=FALSE`

)- ...
Additional arguments (none implemented)

##### Value

RasterLayer

##### See Also

##### Examples

```
# NOT RUN {
r <- raster(ncol=10, nrow=10)
set.seed(0)
r[] <- runif(ncell(r))
r[r < 0.2 ] <- 0
r[r > 0.8] <- 1
r[r > 0 & r < 1 ] <- 0.5
Which(r, cells=TRUE)
Which(r > 0.5, cells=TRUE)
s1 <- r > 0.5
s2 <- Which(r > 0.5)
s1[1:15]
s2[1:15]
# this expression
x1 <- Which(r, na.rm=FALSE)
# is the inverse of
x2 <- r==0
# }
```

*Documentation reproduced from package raster, version 2.9-5, License: GPL (>= 3)*

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