stars (version 0.5-0)

st_apply: st_apply apply a function to one or more array dimensions

Description

st_apply apply a function to array dimensions: aggregate over space, time, or something else

Usage

# S3 method for stars
st_apply(
  X,
  MARGIN,
  FUN,
  ...,
  CLUSTER = NULL,
  PROGRESS = FALSE,
  FUTURE = FALSE,
  rename = TRUE,
  .fname
)

Arguments

X

object of class stars

MARGIN

see apply; index number(s) or name(s) of the dimensions over which FUN will be applied

FUN

see apply

...

arguments passed on to FUN

CLUSTER

cluster to use for parallel apply; see makeCluster

PROGRESS

logical; if TRUE, use pbapply::pbapply to show progress bar

FUTURE

logical;if TRUE, use future.apply::future_apply

rename

logical; if TRUE and X has only one attribute and FUN is a simple function name, rename the attribute of the returned object to the function name

.fname

function name for the new attribute name (if one or more dimensions are reduced) or the new dimension (if a new dimension is created); if missing, the name of FUN is used

Value

object of class stars with accordingly reduced number of dimensions; in case FUN returns more than one value, a new dimension is created carrying the name of the function used; see the examples.

Examples

# NOT RUN {
tif = system.file("tif/L7_ETMs.tif", package = "stars")
x = read_stars(tif)
st_apply(x, 1:2, mean) # mean band value for each pixel
st_apply(x, c("x", "y"), mean) # equivalent to the above
st_apply(x, 3, mean)   # mean of all pixels for each band
st_apply(x, "band", mean) # equivalent to the above
st_apply(x, 1:2, range) # min and max band value for each pixel
# to get a progress bar also in non-interactive mode, specify:
if (require(pbapply)) { # install it, if FALSE
  pboptions(type = "timer")
}
# }