monthlyComposite {gimms} | R Documentation |
Calculate Monthly Composite Images
Description
Based on a user-defined function, e.g. max
for maximum value
composites (MVC), aggregate half-monthly GIMMS data sets to monthly composites.
Usage
## S4 method for signature 'RasterStackBrick'
monthlyComposite(x, indices, fun = max, cores = 1L, filename = "", ...)
## S4 method for signature 'character'
monthlyComposite(
x,
version = 1L,
pos1 = ifelse(version == 1, 15L, 4L),
pos2 = ifelse(version == 1, 23L, 8L),
fun = max,
cores = 1L,
filename = "",
...
)
Arguments
x |
Multi-layered Raster* object or character vector of
filenames. If the latter applies and 'pos1', 'pos2' are not specified, the
function will try to retrieve monthly indices from
monthlyIndices . Note that the specification of NDVI3g.v0 ENVI
binary files is hereby not allowed and in such a case,
rasterizeGimms should be run beforehand.
|
indices |
numeric . Indices to denote layers or files from
identical months.
|
fun |
function . Used to calculate monthly composite layers,
defaults to max . Note that a separate 'na.rm' argument is
passed down to stackApply via '...' and hence should not be
included here.
|
cores |
integer . Number of cores for parallel computing.
|
filename |
character . Optional output filename passed to
stackApply .
|
... |
Further arguments passed to stackApply (i.e.,
'na.rm') and its underlying writeRaster call.
|
version |
integer (or any other class convertible to
integer ). Specifies GIMMS NDVI3g product version, see 'Details' in
updateInventory .
|
pos1 , pos2 |
integer . If 'x' is a vector of filenames, the first
and last element of the date string to build monthly indices from. Defaults
to the 'version'-specific NDVI3g naming convention, see
monthlyIndices .
|
Value
If length(x) == 2
, a single RasterLayer
object, else a
RasterStack
object with monthly composite layers.
See Also
stackApply
, monthlyIndices
,
writeRaster
.
Examples
data("bale3g.v1")
## select layers from 1981 only
fls <- system.file("extdata/inventory_ecv1.rds", package = "gimms")
fls <- readRDS(fls)[1]
rst <- bale3g.v1[[1:12]]
## aggregate to monthly mvc layers
mvc <- monthlyComposite(rst, indices = monthlyIndices(fls))
[Package
gimms version 1.2.2
Index]