STAC Guidance for Metadata Creators

STAC Guidance for Metadata Creators

This guidance is for including a STAC Catalog as a resource in a metadata record. Providing a STAC Catalog as a resource will allow GeoPlatform to discover the catalog and include it in the GeoPlatform STAC Catalog.

STAC Background:

The SpatioTemporal Asset Catalog (STAC) specification provides a common language to describe a range of geospatial information, so it can more easily be indexed and discovered. A ‘spatiotemporal asset’ is any file that represents information about the earth captured in a certain space and time.

The STAC Specification consists of 4 semi-independent specifications. Each can be used alone, but they work best in concert with one another.

  • STAC Item is the core atomic unit, representing a single spatiotemporal asset as a GeoJSON feature plus datetime and links.*

  • STAC Catalog is a simple, flexible JSON file of links that provides a structure to organize and browse STAC Items. A series of best practices helps make recommendations for creating real world STAC Catalogs.*

  • STAC Collection is an extension of the STAC Catalog with additional information such as the extents, license, keywords, providers, etc that describe STAC Items that fall within the Collection.*

  • STAC API provides a RESTful endpoint that enables search of STAC Items, specified in OpenAPI, following OGC’s WFS 3.*

https://stacspec.org/

STAC Catalog as a Resource

Provide the link to the STAC Catalog as a metadata resource identifying the application profile as a SpatioTemporal Asset Catalog. The information below is from the FGDC Technical Guidance: Data.gov and The GeoPlatform Metadata Recommendations in the section titled: “Provide Direct URLs to Data Download”.

ISO 19115

Provide the download URL as either:

MD\_Metadata.identificationInfo>MD\_DataIdentification.citation>CI\_Citation.citedResponsibleParty>CI\_ResponsibleParty. contactInfo>CI\_Contact.onlineResource>CI\_OnlineResource.linkage

or

MD\_Metadata.distributionInfo>MD\_Distribution.transferOptions>MD\_DigitalTransferOptions.onLine>CI\_OnlineResource.linkage

Provide the download file name as either:`

MD\_Metadata.identificationInfo>MD\_DataIdentification.citation>CI\_Citation.citedResponsibleParty>CI\_ResponsibleParty. contactInfo>CI\_Contact.onlineResource>CI\_OnlineResource.name

or

MD\_Metadata.distributionInfo>MD\_Distribution.transferOptions>MD\_DigitalTransferOptions.onLine>CI\_OnlineResource.name

Provide a description of the download resource to give consumers much needed context for the URL as either:

MD\_Metadata.identificationInfo>MD\_DataIdentification.citation>CI\_Citation.citedResponsibleParty>CI\_ResponsibleParty. contactInfo>CI\_Contact.onlineResource>CI\_OnlineResource.description

or

MD\_Metadata.distributionInfo>MD\_Distribution.transferOptions>MD\_DigitalTransferOptions.onLine>CI\_OnlineResource.description

Indicate the format of the download as a SpatioTemporal Asset Catalog:

MD\_Metadata.identificationInfo>MD\_DataIdentification.citation>CI\_Citation.citedResponsibleParty>CI\_ResponsibleParty. contactInfo>CI\_Contact.onlineResource>CI\_OnlineResource.applicationProfile

or

MD\_Metadata.distributionInfo>MD\_Distribution.transferOptions>MD\_DigitalTransferOptions.onLine> CI\_OnlineResource.applicationProfile

Example using the Landsat STAC Catalog

<gmd:CD_OnlineResource>
  <gmd:linkage>
    <gmd:URL>https://landsat-stac.s3.amazonaws.com/catalog.json</gmd:URL>
  </gmd:linkage>
  <gmd:protocol>
    <gco:CharacterString>STAC</gco:CharacterString>
  </gmd:protocol>
  <gmd:applicationProfile>
    <gco:CharacterString>SpatioTemporal Asset Catalog</gco:CharacterString>
  </gmd:applicationProfile>
  <gmd:name>
    <gco:CharacterString>Landsat STAC Catalog</gco:CharacterString>
  </gmd:name>
  <gmd:description>
    <gco:CharacterString>SpatioTemporal Asset Catalog for Landstat Data</gco:CharacterString>
  </gmd:description>
<gmd:CI_OnlineResource>

More information