Skip to contents

Fetch GLASS granules for a variant, ROI and date range in one call

Source: R/fetch.R
glass_fetch.Rd

glass_fetch() orchestrates the full pipeline of the legacy scripts: registry variant -> glass_tiles_for_sf() (or explicit tiles) -> glass_doys() -> glass_list_files() per composite folder -> glass_download().

Usage

glass_fetch(
  variant_id,
  from,
  to,
  roi = NULL,
  tiles = NULL,
  doys_mode = c("span", "start"),
  out_dir,
  dry_run = FALSE,
  delay = 1,
  overwrite = FALSE,
  quiet = FALSE,
  progress = NULL
)

Arguments

variant_id

Registry variant key.

from, to

Date range ("YYYY-mm-dd" or Date). Ignored for static file collections (layout = "flat", e.g. AGB, KGClim, Crops): those are whole-file exchanges, so the full file list is fetched instead.

roi

Optional spatial selection (sf/sfc). Mutually exclusive with tiles. Leave both roi and tiles unset for global (CMG) variants that carry no tiles.

tiles

Optional explicit tile ids, e.g. c("h28v05") or c("h27v05", "h28v05").

doys_mode

DOY selection mode passed to glass_doys() ("span" keeps every composite overlapping the range; "start" keeps only those starting inside it). Same semantics in the self-scan branch, calibrated against the composite dates found in the year folder.

out_dir

Destination directory.

dry_run

Only return the file manifest without downloading.

delay, overwrite, quiet, progress

Passed to glass_download().

Value

A tibble manifest; with download status when not a dry run.

Details

Three archive shapes are handled:

  • layout = "flat" — static whole-file exchanges (AGB, KGClim, Crops, Albedo ABI climatologies). The date range is ignored and the full root listing is returned.

  • cadence known (cadence_days): composite DOY folders are computed with glass_doys() and each <year>/<doy>/ folder is listed.

  • cadence unknown (cadence_days is NA): self-scan. Each year folder intersecting the range is listed once and granules are filtered by composite codes parsed from their filenames (A{yyyy}{ddd}, month codes such as .2010xx., or trailing 7-digit year codes). Single- or irregularly spaced composites keep the whole year; regular ones follow doys_mode. This covers products whose granules sit directly in year folders (FVC, Albedo AVHRR/MIX/0.5D, PAR, RN, SM, LST/AVHRR Daily-ODC, NDVI/MODIS 0.25°, TPSCE, AWGF LST), roots wrapped one level by a version dir (NPP), and year folders holding DOY sub-folders (Albedo MODIS 250M).

  • geographic 1° tile collections (HiGLASS LAI/FAPAR 20m, FAPAR HR): root/<nXXXeYYY>/ holds one yearly file per tile. Selection follows tiles (e.g. c("n045e120")) or, with a drawn roi, the bbox floors of it; a yearly _2018_ token is parsed for date filtering. Without a tile selection the root holds > 60 tiles and nothing is downloaded until you narrow the ROI.

The self-scan keeps the fetch path tolerant to registry omissions: when an unmeasured variant turns out to have a different layout than the skeleton assumption, it still resolves granules from what the archive itself reports.

Examples

if (FALSE) { # \dontrun{
# verified cadence (fast path)
glass_fetch("LAI_MODIS_250M", "2018-08-01", "2018-08-31", tiles = "h28v05")
# cadence unknown (self-scan path)
glass_fetch("FVC_AVHRR_0_5D", "2018-08-01", "2018-09-30", dry_run = TRUE)
} # }