Set built-in GDAL pixel functions of a VRT stack object

Set built-in GDAL pixel functions of a VRT stack object

Usage

vrt_set_gdal_pixelfun(x, pixfun, ..., band_idx)

# S3 method for class 'vrt_block'
vrt_set_gdal_pixelfun(x, pixfun, ..., band_idx = NULL)

# S3 method for class 'vrt_collection'
vrt_set_gdal_pixelfun(x, pixfun, ..., band_idx = NULL)

Arguments

x

A vrt_stack object

pixfun

A built-in GDAL pixel function. See details for a list of available functions.

...

named arguments used within the pixel function see details.

band_idx

The indices of the bands to set the pixel function for. If NULL, the pixel function is set for all bands.

Details

The documentation for the GDAL pixel functions can be found at https://gdal.org/en/stable/drivers/raster/vrt.html#built-in-pixel-functions

Where a pixel function requires arguments, these can be passed as named arguments, in line with the specified naming in PixelFunctionArguments of the table at the above link.

Examples

s2files <- fs::dir_ls(system.file("s2-data", package = "vrtility"))
ex_collect <- vrt_collect(s2files)

t_block <- ex_collect[[1]][[1]]
ex_stack <- ex_collect |>
  vrt_set_maskfun(
    mask_band = "SCL",
    mask_values = c(0, 1, 2, 3, 8, 9, 10, 11),
    drop_mask_band = TRUE
  ) |>
  vrt_warp(
    t_srs = t_block$srs,
    te = t_block$bbox,
    tr = t_block$res
  ) |>
  vrt_stack()

plot(
  vrt_set_gdal_pixelfun(
    ex_stack,
    pixfun = "min",
    propagateNoData = TRUE
  ),
  bands = c(3, 2, 1)
)
#> ℹ You a plotting a warped raster - this might be okay...
#>   But, If this is taking a long time you are probably better
#>   off saving the file first with `vrt_compute` and then plotting
#>   with `plot_raster_src()`.


plot(
  vrt_set_gdal_pixelfun(
    ex_stack,
    pixfun = "min"
  ),
  bands = c(3, 2, 1)
)
#> ℹ You a plotting a warped raster - this might be okay...
#>   But, If this is taking a long time you are probably better
#>   off saving the file first with `vrt_compute` and then plotting
#>   with `plot_raster_src()`.