All notable changes to this project will be documented in this file.
The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.
v1.1.0 - 2025-06-21
- Sortables (e.g. endpoint
GET /sortables) - Sort for Collections (i.e. Collection Search)
- Clarify that
directionis optional
v1.0.0 - 2023-09-28
- Updated maturity to Stable.
v1.0.0-rc.2 - 2022-11-01
- Clarify that the names for sortable fields can either be prefixed by
propertiesor not.
v1.0.0-rc.1 - 2022-03-17
- The CQL2 Accent and Case-insensitive Comparison
(
http://www.opengis.net/spec/cql2/1.0/conf/accent-case-insensitive-comparison) conformance class adds the ACCENTI and CASEI functions for case-insensitive comparison. These replace the UPPER and LOWER psuedo-functions that were previously part of the Advanced Comparison Operators class.
- Query Extension is no longer deprecated.
- Children conformance class now requires the /children endpoint includes all child catalogs or collections
referenced via
childlink relations from the Landing Page - Clarified behavior of Transaction Extension endpoints:
- PUT and PATCH of a body that changes the
collectionoridis disallowed. - POST, PUT, and PATCH do not need to include the
collectionattribute, as it should be derived from the URL. - POST and PUT can be used with a body that is at least a GeoJSON Feature, but does not have to be an Item, but for which the server can derive a valid Item, e.g., by populating the id and collection fields or adding links
- Likewise, POST can be used with a body of a FeatureCollection that contains features that meet the same constraints.
- PUT and PATCH of a body that changes the
- Specifications now use the term "must" instead of "shall". The semantics of these words are identical.
- Conformance class for Item Search Filter is now
https://api.stacspec.org/v1.0.0-beta.5/item-search#filter, whereas before it was incorrectly stated ashttps://api.stacspec.org/v1.0.0-beta.5/item-search#filter:item-search-filter
v1.0.0-beta.5 - 2022-01-14
- Added
STAC API - Browseableconformance class - Added
STAC API - Childrenconformance class - Added description of how to support both search and browse in an API.
- The paging mechanism via a Link with rel
nextorprevas defined for Item Search can also be used for the STAC API - Features endpoint/collections/{collection_id}/items, as described in OAFeat. - The paging mechanism via a Link with rel
nextorprevas defined for items can also be used for the STAC API - Features and STAC API - Collections endpoint/collections.
- Limit parameter semantics now match OAFeat. Previously, the behavior was not precisely defined.
- Filter Extension updates to align with changes to OAFeat CQL2 spec
- Updated all "CQL" usages to "CQL2"
- Most conformance class URIs are now prefixed with
http://www.opengis.net/spec/cql2/instead ofhttp://www.opengis.net/spec/ogcapi-features-3/ - Conformance classes
http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/basic-cql,http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/cql-text, andhttp://www.opengis.net/spec/ogcapi-features-3/1.0/conf/cql-jsonhave hadcqlreplaced withcql2(in addition to the prefix change) to becomehttp://www.opengis.net/spec/cql2/1.0/conf/basic-cql2,http://www.opengis.net/spec/cql2/1.0/conf/cql2-text, andhttp://www.opengis.net/spec/cql2/1.0/conf/cql2-json - Significant changes to CQL2 JSON format, now using
opandargsstructure - Spatial operator
INTERSECTSis nowS_INTERSECTS - Temporal operator
ANYINTERACTSis nowT_INTERSECTS - Updated Example 3 (now Example 5) to make it clear that property to property comparisons require the Property-Property Comparisons conformance class
- The CQL2 Case-insensitive Comparison
(
http://www.opengis.net/spec/cql2/1.0/conf/case-insensitive-comparison) conformance class that adds UPPER/LOWER terms or function CASEI for case-insensitive comparison has not been added to this spec yet, since the definition in CQL2 is in flux.
service-descendpoint may return any service description format, typically a machine-consumable one (previous restricted required to be OpenAPI 3.0 JSON)service-docendpoint may return any service description format, typically a human-consumable one (previous restricted required to be HTML)
- Collection conformance class URI should be
https://api.stacspec.org/v1.0.0-beta.XXX/collectionsinstead ofhttp://stacspec.org/spec/api/1.0.0-beta.XXX/extensions/collections - definition of Item object was missing
propertiesas an attribute - Filter Extension - examples of using intervals and timestamps in CQL2 were incorrect and have been fixed
- Filter Extension - examples are updated so that text and json examples are equivalent
v1.0.0-beta.4 - 2021-10-05
- Support binding Sort, Fields, and Context Extensions to STAC Features items resource
endpoint (
/collections/{collectionId}/items) - In Collections, added
canonicalrel type, added/and/apito list of endpoints - In Item Search, added endpoint table
- Filter Extension - query language is now referred to as "CQL2" rather than CQL
- Filter Extension now uses OAFeat Part 3 conformance class URIs
- Filter Extension - The following changes have been made to the Filter Extension conformance classes to align with changes to the OAFeat CQL draft. All classes
whose names have changed also have changed conformance URI strings.
- "Basic CQL" now includes the "not equal" operator (
<>) - "Basic CQL" has always supported datetime comparisons, but this is now explicitly mentioned
- "Enhanced Comparison Operators" has been renamed "Advanced Comparison Operators". This is the same as the OAFeat CQL definition, except
that it does not require the
upperandlowerfunctions. - "Enhanced Spatial Operators" has been renamed to just "Spatial Operators" (not to be confused with Basic Spatial Operators)
- "Basic Temporal Operators" and "Enhanced Temporal Operators" have merged into "Temporal Operators"
- "Functions" has been renamed "Custom Functions"
- "Arithmetic" has been renamed "Arithmetic Expressions"
- "Arrays" has been renamed "Array Operators"
- "Queryable Second Operand" has been renamed "Property-Property Comparisons"
- "Basic CQL" now includes the "not equal" operator (
- The required Link Relations and endpoints for each conformance class now use the wording of 'shall' instead of 'should'. While this technically changes the semantics, it was generally understood previously the semantics were those of 'shall' (must).
- Explicitly state that the
/childrenendpoint can return Catalog and Collection objects that have fewer fields than are available through other endpoints.
v1.0.0-beta.3 - 2021-08-06
- Added STAC API - Collections definition (subset of STAC API - Features)
- More thorough definitions for valid
datetimeandbboxquery parameter values.
- Query extension not deprecated; recommendation to use Filter (radiantearth/stac-api-spec#157)
- Filter Extension conformance classes refactored to better align with STAC API use cases.
- Renamed conformance class "Queryable First Operand" (https://api.stacspec.org/v1.0.0-beta.3/item-search#filter:queryable-first-operand) to "Queryable Second Operand" (https://api.stacspec.org/v1.0.0-beta.3/item-search#filter:queryable-second-operand)
- Remove stac_version and stac_extensions fields in ItemCollection
v1.0.0-beta.2 - 2021-06-01
- Added Filter extension to integrate OAFeat Part 3 CQL
- Catalog and Collection definitions now have required field "type"
- Added recommendation to enable CORS for public APIs
- Updated all STAC versions to 1.0.0
- Passing the
idsparameter to an item search does not deactivate other query parameters #125 - The first extent in a Collection is always the overall extent, followed by more specific extents. opengeospatial/ogcapi-features#520
- Query extension is now deprecated. Replaced by the Filter extension using OGC CQL.
- Updated text description of root ('/') endpoint (also called landing page) that the return type is a Catalog
v1.0.0-beta.1 - 2020-12-10
- The landing page returns the conformance classes in a property
conformsTo, which mirrorsGET /conformancesfrom OGC APIs. - Conformance classes for all the major functionality and extensions, to be referenced in a new
conformsToJSON object in the landing page. - Fragments: reusable OpenAPI documents for sort, filter, fields and context, along with explanation of how they work.
- ItemCollection moved from STAC Core to this repo.
- Major re-organization of the content and directory structure to make better conformance classes.
- STAC API Core is the landing page (a STAC catalog and conformance information).
- Item Search is the
searchcross-collection item search resource. - STAC API - Features is the OGC API - Features standards to be used in a STAC API.
- Extensions are specified in the relevant functionality directory, though they can share openapi yaml's in the 'fragments' directory.
- Updated to STAC specification version 1.0.0-beta.2
- Named explicit supported STAC core versions to be from 0.9.0 up to (and not including) 2.0.0
- Context Extension OpenAPI spec was updated to remove the no longer used
nextattribute - Added root endpoint Link
searchmust havetypeofapplication/geo+json - Corrected the description of endpoint
/collectionsto say it returns an object per OAFeat, instead of an array of Collection - Updated transaction extension so it aligns with OGC API - Features Part 4: Simple Transactions
- BBOX openapi yaml to only allow 4 or 6 element arrays
- Fixed invalid OpenAPI files
See the stac-spec CHANGELOG for STAC API releases prior to or equal to version 0.9.0.