cellSize: Area covered by each raster cell

cellSizeR Documentation

Area covered by each raster cell


Compute the area covered by individual raster cells.

Computing the surface area of raster cells is especially relevant for longitude/latitude rasters.

But note that for both angular (longitude/latitude) and for planar (projected) coordinate reference systems raster cells sizes are generally not constant, unless you are using an equal-area coordinate reference system.

For planar CRSs, the area is therefore not computed based on the linear units of the coordinate reference system, but on the *actual* area by transforming cells to longitude/latitude. If you do not want that correction, you can use transform=FALSE or init(x, prod(res(x)))


## S4 method for signature 'SpatRaster'
cellSize(x, mask=FALSE, lyrs=FALSE, unit="m", transform=TRUE, rcx=100, filename="", ...)





logical. If TRUE, cells that are NA in x are also NA in the output


logical. If TRUE and mask=TRUE, the output has the same number of layers as x. That is only useful if cases where the layers of x have different cells that are NA


character. One of "m", "km", or "ha"


logical. If TRUE, planar CRS data are transformed to lon/lat for accuracy


positive integer. The maximum number of rows and columns to be used to compute area of planar data if transform=TRUE. If x has more rows and/or columns, the raster is aggregated to match this limit, and values for the original cells are estimated by bilinear interpolation (see resample). This can save a lot of time


character. Output filename


additional arguments for writing files as in writeRaster



See Also



# SpatRaster 
r <- rast(nrows=18, ncols=36)
v <- 1:ncell(r)
v[200:400] <- NA
values(r) <- v

# size of each raster cell
a <- cellSize(r)

# illustration of distortion
r <- rast(ncols=90, nrows=45, ymin=-80, ymax=80)
m <- project(r, "+proj=merc")

bad <- init(m, prod(res(m)) / 1000000, names="naive")
good <- cellSize(m, unit="km", names="corrected")
plot(c(good, bad), nc=1, mar=c(2,2,1,6))

terra documentation built on Oct. 13, 2023, 5:08 p.m.