This document explains the structure and content of a SpatioTemporal Asset Catalog (STAC) ItemCollection. An ItemCollection is a GeoJSON FeatureCollection that is augmented with foreign members relevant to a STAC entity.
Similarly to the relationship between a GeoJSON Feature and a STAC Item, a STAC ItemCollection should be a valid GeoJSON FeatureCollection to allow interoperability with existing tools that support GeoJSON.
The same ItemCollection definition is currently only used by the /search endpoint.
The search endpoint enables dynamic
queries, for example selecting all Items in Hawaii on June 3, 2015, but the results they return are an
ItemCollection of Items.
Items are represented in JSON format and are very flexible. Any JSON object that contains all the required fields is a valid STAC ItemCollection.
- Examples:
- See the minimal example, as well as a more complete example. There are more real world inspired samples in the examples/ folder.
- Real world implementations are also available.
- JSON Schema
This is still an early version of the STAC spec, expect that there may be some changes before everything is finalized.
Implementations are encouraged, however, as good effort will be made to not change anything too drastically. Using the specification now will ensure that needed changes can be made before everything is locked in. So now is an ideal time to implement, as your feedback will be directly incorporated.
This object describes a STAC ItemCollection. The fields type and features are inherited from GeoJSON FeatureCollection.
| Field Name | Type | Description |
|---|---|---|
| stac_version | string | REQUIRED. The STAC version the ItemCollection implements. |
| stac_extensions | [string] | A list of extensions the ItemCollection implements. |
| type | string | REQUIRED. Always "FeatureCollection" to provide compatibility with GeoJSON. |
| features | STAC Item | REQUIRED A possibly-empty array of Items. |
| links | Link Object | An array of Links related to this ItemCollection. |
stac_version: In general, STAC versions can be mixed, but please keep the recommended best practices in mind.
stac_extensions: A list of extensions the ItemCollection implements. The list contains URLs to the JSON Schema files it can be validated against. For official content extensions, a "shortcut" can be used. This means you can specify the folder name of the extension, for example single-file-stac for the Single File STAC extension. This does not apply for API extensions. If the versions of the extension and the item diverge, you can specify the URL of the JSON schema file.
This list must only contain extensions that extend the ItemCollection itself, see the the 'Scope' column in the list of extensions. It must not contain extensions that extend the Items, these must be specified in the Items directly.
- The Context Extension adds additional fields to STAC ItemCollection relevant to their use as search results.
- The Single File STAC Extension provides a set of Collections and Items as a single file catalog.