cellSize | R Documentation |
Compute the area covered by individual raster cells. Computing the surface area of raster cells is particularly relevant for longitude/latitude rasters.
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, correcting for distortion. If you do not want that, you can instead use init(x, prod(res(x)))
## S4 method for signature 'SpatRaster' cellSize(x, mask=TRUE, unit="m", transform=TRUE, rcx=100, filename="", ...)
x |
SpatRaster |
mask |
logical. If |
unit |
character. One of "m", "km", or "ha" |
transform |
logical. If |
rcx |
positive integer. The maximum number of rows and columns to be used to compute area of planar data if |
filename |
character. Output filename |
... |
additional arguments for writing files as in |
numeric. The area of each cell, expressed in square meters, square kilometers, or hectares.
expanse
# 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))
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.