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Remove rasters and vectors from the GRASS cache

Source: R/mow.r
mow.Rd

fasterRaster functions attempt to delete rasters and vectors in the GRASS cache, but not all intermediate files can be removed. This function can be used to clear the cache of extraneous rasters and vectors.

Calling this function inside another function's environment and defining x as "*" can be very dangerous, as it will detect objects outside of that environment, and thus delete any rasters/vectors outside that environment. Here is a guide:

  • To delete files associated with a single GRaster or GVector, use mow(GRaster_to_unlink) or mow(GVector_to_unlink). To remove all rasters, all vectors, or all rasters and vectors in the GRASS cache that are not linked to a GRaster or GVector, use mow("*"). To remove all rasters or all vectors in the GRASS cache, use mow("*", type = "rasters") or mow("*", type = "vectors"). To remove all rasters or all vectors in the GRASS cache except for certain ones, use mow("*", unlinked = FALSE, keep = list(GRaster_to_keep, GVector_to_keep)). You can combine this with the keep argument to retain specific rasters or vectors. For example, you can use mow("*", unlinked = FALSE, type = "rasters", keep = list(GRaster_to_keep)).

Usage

mow(
  x = "unlinked",
  pos = NULL,
  type = NULL,
  keep = NULL,
  verbose = TRUE,
  ask = TRUE
)

Arguments

x

Any of:

  • "unlinked" (default): Delete GRASS rasters and/or vectors that are unlinked to GRasters or GVectors in the environment in which the function was called, or the environment named in pos.

  • A GRaster or GVector: Delete the GRASS raster or vector pointed to by this object.

  • A list of GRasters and/or GVectors: Delete the GRASS raster(s) and/or vector(s) pointed to by these objects.

  • "*": Delete all GRASS rasters and/or vectors pointed to by objects in the environment named in pos. Only objects in keep will not be deleted.

pos

Either NULL (default), or an environment. This is used only if x is "unlinked" or "*". In that case, if pos is NULL, the environment in which this function was called will be searched for GRasters and GVectors for removal of their associated GRASS rasters and vectors. Otherwise, the named environment will be searched.

type

Either NULL or a character vector. This is used only if x is "unlinked" or "*". If NULL, all rasters and vectors in the GRASS cache are candidates for deletion. Otherwise, this can be either "rasters", "vectors", or both.

keep

Either NULL (default) or a list() of GRasters and/or GVectors that you want to retain. This is used only if x is "unlinked" or "*". The rasters and vectors in GRASS pointed to by these objects will not be deleted.

verbose

Logical: If TRUE (default), report progress.

ask

Logical: If TRUE (default), prompt for reassurance. This is used only if x is "unlinked" or "*".

Value

Invisibly returns a named vector with the number of rasters and vectors deleted.

See also

terra::tmpFiles()

Examples

if (grassStarted()) {

# Setup
madElev <- fastData("madElev")
elev <- fast(madElev)

mow(elev, ask = TRUE) # delete GRASS raster attached to `elev`

}