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Fetch STAC-hosted rasters via gdalcubes

Source: R/dft_stac_fetch.R
dft_stac_fetch.Rd

Query a STAC catalog, build a gdalcubes image collection, and extract per-year rasters cropped and masked to the AOI. Works with any STAC collection hosting single-band classified rasters (IO LULC, ESA WorldCover, custom COGs).

Usage

dft_stac_fetch(
  aoi,
  source = "io-lulc",
  years = NULL,
  stac_url = NULL,
  collection = NULL,
  asset = NULL,
  res = 10,
  crs = NULL,
  dt = "P1Y",
  aggregation = "first",
  resampling = "near",
  cache_dir = NULL,
  force = FALSE,
  sign_fn = rstac::sign_planetary_computer()
)

Arguments

aoi

An sf polygon defining the area of interest.

source

Character. A known source name passed to dft_stac_config(). Ignored when stac_url, collection, and asset are all provided.

years

Integer vector of years to fetch. When NULL, uses available_years from dft_stac_config().

stac_url

Character. STAC API endpoint URL. Overrides source.

collection

Character. STAC collection ID. Overrides source.

asset

Character. Asset name within each STAC item. Overrides source.

res

Numeric. Output pixel size in CRS units (default 10).

crs

Character. Target CRS as an EPSG string (e.g. "EPSG:32609"). When NULL, auto-detected from the AOI centroid's UTM zone.

dt

Character. ISO 8601 duration for the temporal aggregation window (default "P1Y").

aggregation

Character. Temporal aggregation method (default "first"). Use "median" for multi-scene composites.

resampling

Character. Spatial resampling method (default "near" for categorical data).

cache_dir

Character. Cache directory path. When NULL, uses dft_cache_path().

force

Logical. Re-fetch even if cached (default FALSE).

sign_fn

A signing function for STAC assets. Default is rstac::sign_planetary_computer().

Value

A named list of terra::SpatRaster objects, one per year. The STAC items are attached as attr(, "stac_items") for use with dft_stac_classes().