area | R Documentation |

Raster objects: Compute the approximate surface area of cells in an unprojected (longitude/latitude) Raster object. It is an approximation because area is computed as the height (latitudinal span) of a cell (which is constant among all cells) times the width (longitudinal span) in the (latitudinal) middle of a cell. The width is smaller at the poleward side than at the equator-ward side of a cell. This variation is greatest near the poles and the values are thus not very precise for very high latitudes.

SpatialPolygons: Compute the area of the spatial features. Works for both planar and angular (lon/lat) coordinate reference systems

```
## S4 method for signature 'RasterLayer'
area(x, filename="", na.rm=FALSE, weights=FALSE, ...)
## S4 method for signature 'RasterStackBrick'
area(x, filename="", na.rm=FALSE, weights=FALSE, ...)
## S4 method for signature 'SpatialPolygons'
area(x, ...)
```

`x` |
Raster* or SpatialPolygons object |

`filename` |
character. Filename for the output Raster object (optional) |

`na.rm` |
logical. If |

`weights` |
logical. If |

`...` |
additional arguments as for |

If `x`

is a RasterStack/Brick, a RasterBrick will be returned if `na.rm=TRUE`

. However, if `na.rm=FALSE`

, a RasterLayer is returned, because the values would be the same for all layers.

If `x`

is a Raster* object: RasterLayer or RasterBrick. Cell values represent the size of the cell in km2, or the relative size if `weights=TRUE`

. If the CRS is not longitude/latitude the values returned are the product of the cell resolution (typically in square meter).

If `x`

is a SpatialPolygons* object: area of each spatial object in squared meters if the CRS is longitude/latitude, or in squared map units (typically meter)

```
r <- raster(nrow=18, ncol=36)
a <- area(r)
p <- shapefile(system.file("external/lux.shp", package="raster"))
p$area <- round(area(p) / 10000000,1)
p$area
```

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