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STAC And GeoTIFF Schema

The store layout is:

<cache-root>/
  <request-hash>/
    stac-item.json
    assets/
      prior/
        2024-07/
          brdf_iso_red.tif
          brdf_vol_red.tif
      uncertainty/
        2024-07/
          brdf_iso_red.tif
          brdf_vol_red.tif

Prior Assets

Each assets/prior/<composite-period>/<band>.tif file is a tiled, DEFLATE-compressed single-band GeoTIFF with no overviews. If no composite_period is provided by the caller, the file is written as assets/prior/<band>.tif. The period and band path tokens are filesystem-safe forms of the supplied labels; a monthly label like 2024-07 is preserved as-is.

  • Data type: uint16
  • Scale factor: 10000
  • Stored value: round(prior * 10000)
  • Nodata: 65535
  • Bands: exactly one band per GeoTIFF

Uncertainty Assets

Each assets/uncertainty/<composite-period>/<band>.tif file is a tiled, DEFLATE-compressed single-band GeoTIFF with no overviews. If no composite_period is provided by the caller, the file is written as assets/uncertainty/<band>.tif.

  • Data type: uint8
  • Unit: percent relative uncertainty
  • Valid range: 0 to 200
  • Suspicious or missing value: 255
  • Bands: exactly one uncertainty band per GeoTIFF

STAC Item

stac-item.json uses STAC 1.0.0 plus the projection and raster extensions.

Important fields:

  • properties.surface:schema_version: package output schema version
  • properties.surface:prior_type: prior family, currently brdf
  • properties.surface:composite_period: optional caller-defined period label, such as 2024-07
  • properties.surface:asset_layout: single-band-geotiff-per-band
  • properties.surface:band_names: ordered prior band list
  • assets.*.href: relative path to a one-band GeoTIFF
  • assets.*.surface:asset_kind: prior or uncertainty
  • assets.*.surface:band_name: source prior band name
  • assets.*.surface:band_index: zero-based band order
  • proj:wkt2: native CRS
  • proj:shape: raster shape
  • proj:transform: affine transform
  • proj:bbox: native-projection bounds
  • bbox and geometry: caller-supplied WGS84 bounds and geometry when available

Each STAC asset has exactly one raster:bands entry. Prior assets advertise uint16 with scale 0.0001; uncertainty assets advertise uint8, percent units, valid statistics from 0 to 200, and nodata 255.

The STAC Item is the package-neutral output contract.