STAC assets

Learn how to analyze STAC assets.


Overview

A STAC asset is a geospatial feature of a STAC item. For example, bands in an optical image, thumbnails, and metadata files represent different STAC assets.

The cloud-native asset model (CNAM) format transforms an UP42 asset into individual geospatial features available for immediate download. Regardless of provider or delivery format, UP42 transforms assets into a standard model. CNAM also standardizes the following types of files to enable easier integrations:

Elements of the originally delivered UP42 asset are mapped as individual STAC assets on a STAC item level. Original delivery is mapped as a STAC asset on a STAC collection level.

A diagram showing UP42 assets are mapped on a STAC collection level, and STAC assets are mapped in a STAC item level

You can also access CNAM files using the console.

STAC assets in a STAC item

STAC assets are returned as part of a STAC item response body. You can get STAC assets in one of the following ways:

JSON

    {
  <...>,
  "assets": {
    "mgag5ui3_img_phr1a_ms_202208080011285_sen_6452562101-2.tiff": {
      "href": "https://api.up42.com/v2/assets/e4a15000-890b-445c-82bb-e4364baac40b",
      "title": "Multispectral data",
      "type": "image/tiff; application=geotiff; profile=cloud-optimized",
      "roles": ["data", "multispectral"],
      "gsd": 0.7283,
      "eo:bands": [
        {
          "name": "blue",
          "common_name": "blue",
          "center_wavelength": 0.47,
          "full_width_half_max": 0.07
        },
        {
          "name": "green",
          "common_name": "green",
          "center_wavelength": 0.47,
          "full_width_half_max": 0.07
        },
        {
          "name": "red",
          "common_name": "red",
          "center_wavelength": 0.665,
          "full_width_half_max": 0.038
        }
      ]
    }
  },
  <...>
}
  
ParameterOverview
hrefstring
The URL of a downloadable or a streamable file related to the STAC asset.
titlestring
The STAC asset title.
typestring
The STAC asset media type.
rolesarray of strings
The role of the STAC asset.
gsdfloat
The ground sample distance, in meters.
eo:bandsarray of objects
Electro-optical bands. For more information, see extension specification.
Parameters of the eo:bands array
namestring
The name of the band.
common_namestring
The name commonly used to refer to the band to make it easier to search for bands. For more information, see the list of common band names.
center_wavelengthfloat
The center wavelength of the band, in micrometers.
full_width_half_maxfloat
Full width at half maximum. The width of the band, as measured at half the maximum transmission, in micrometers.

Roles

Data

RoleDescription
dataA higher-level role for all types of data. The CNAM format transforms all raster assets with the data role into COGs.
multispectralAn asset related to the multispectral band.
panchromaticAn asset related to the panchromatic band.

Metadata

RoleDescription
metadataA higher-level role for all types of metadata.
bundleDelivery metadata that contains information about both types of bands, panchromatic and multispectral.
extendedDetailed metadata for multispectral and panchromatic bands.
iso-19115ISO 19115-1:2014 metadata.
licenseAn end-user license agreement (EULA).
lineageProcessing, ground, or strip lineage.
lutA Look-Up-Table with rendering of color curves in a reflectance product.
quality-elevationQuality elevation metadata.
stacSTAC-related metadata.
stereoStereo metadata.
tile-infoTiling metadata.
toa-factorsTop-of-atmosphere reflectance metadata.
angleSensor viewing angle model coefficients.
digestDigest metadata.
auxiliaryAuxiliary metadata.

Previews

RoleDescription
overviewA preview image of higher resolution than thumbnail.
thumbnailA low-resolution preview image, usually up to 600×600 px.
visualA full-resolution version of the data, processed for visual use.

Masks

RoleDescription
data-maskA higher-level role for all types of masks. The CNAM format transforms all vector assets with the data-mask role into GeoJSON files.
cloudA cloud mask. If an asset has cloud coverage of 5% or lower, cloud masks won’t be provided.
detector-qualityA quality detector mask.
footprintA footprint.
roiA region of interest mask.
saturationA saturation mask.
technical-indexA technical index mask.
visibilityA visibility mask.
water-maskA water detection mask.
cloud-shadowA cloud shadow detection mask.
snow-iceA snow and ice detection mask.

Other

RoleDescription
indexSpectral indexes.
rpcRational polynomial coefficients.
temperatureA surface temperature band.
emissivityAn emissivity band.

Limitations

CNAM is only available for assets added to storage starting in 2023.

Not all geospatial collections are supported. To get a list of supported collections, see Introduction to STAC.