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Write AlphaEarth tiles as virtual rasters (VRT)

Source: R/vrt.R
as_vrt.Rd

Materialises the selected tiles as lightweight GDAL VRT files that point at the remote COGs (via /vsicurl/). Two on-disk formats are supported for VRTs:

  • "stack": one multi-band VRT per tile, referencing every requested band (ae_<tile>_<year>.vrt);

  • "bands": one single-band VRT per band (ae_<tile>_<band>_<year>.vrt).

Each tile keeps its native UTM CRS (no reprojection). Existing files are reused unless overwrite = TRUE.

Usage

as_vrt(
  x,
  output_dir,
  bands = NULL,
  roi = NULL,
  layout = c("stack", "bands"),
  overwrite = FALSE,
  progress = TRUE,
  multicores = 1L
)

Arguments

x

An sf object returned by search().

output_dir

Directory where the VRTs are written (created if needed).

bands

Character vector of embedding bands to reference, from A00 to A63 (defaults to all 64 bands).

roi

Optional region of interest used to crop each tile. Defaults to NULL (full tiles).

layout

One of "stack" (one multi-band VRT per tile) or "bands" (one VRT per band).

overwrite

Logical. Re-write files that already exist. Defaults to FALSE.

progress

Logical. Show a progress bar. Defaults to TRUE.

multicores

Integer. Number of parallel workers used to write the files. Defaults to 1 (sequential). Values above 1 write tiles concurrently.

Value

A tibble (invisible) with one row per written file.

See also

search(), download(), as_cube()

Examples

if (FALSE) { # \dontrun{
  tiles <- alphaearth::search(
    roi = my_roi,
    start_date = "2020",
    end_date   = "2020"
  )

  # one multi-band VRT per tile
  vrts <- alphaearth::as_vrt(tiles, output_dir = "embeddings")

  # one VRT per embedding dimension
  vrts <- alphaearth::as_vrt(
    x = tiles,
    output_dir = "embeddings",
    bands = c("A00", "A01"),
    layout = "bands"
  )
} # }