zonalDT {rasterDT} | R Documentation |
Speedy Zonal Statistics
Description
A fast data.table
-based alternative to
raster::zonal()
.
Usage
zonalDT(x, z, fun = sum, na.rm = TRUE)
Arguments
x |
A |
z |
A categorical |
fun |
A name or character string giving the function to be
applied to summarize the values by zone. It needs to return a
single (or at least a length-one vector). If |
na.rm |
Logical. If |
Value
A data.table
with a summary value for each zone.
Author(s)
Joshua O'Brien
Examples
r <- raster(ncols = 10, nrows = 10)
r[] <- runif(ncell(r)) * 1:ncell(r)
z <- r
z[] <- rep(1:5, each = 20)
## for big files, use a character value rather than a function
zonalDT(r, z, "sum")
## for smaller files you can also provide a function
zonalDT(r, z, mean)
zonalDT(r, z, min)
## multiple layers
zonalDT(stack(r, r*10), z, "sum")
[Package rasterDT version 0.3.2 Index]