STAC Common Metadata

CHANGELOG.md

@@ -9,23 +9,27 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 - ItemCollection requires `stac_version` field, `stac_extensions` has also been added
 - A `description` field has been added to Item assets (also Asset definitions extension). 
+- Field `mission` to [Common Metadata fields](item-spec/common-metadata.md).
 - Extensions:
-     - [Version Indicators extension](extensions/version/README.md), adds `version` and `deprecated` fields to STAC Items and Collections
-     - Instrument extension, adds fields: `platform`, `instruments`, `constellation` (all moved from EO and SAR extensions), and `mission`
-     - Data Cube extension can be used in Collections, added new field `description`
-     - Added `description` and `roles` fields to the Asset in the [Asset Extension](extensions/asset/README.md)
+    - [Version Indicators extension](extensions/version/README.md), adds `version` and `deprecated` fields to STAC Items and Collections
+    - Data Cube extension can be used in Collections, added new field `description`
+    - Added `description` and `roles` fields to the Asset in the [Asset Extension](extensions/asset/README.md)
 - STAC API:
-     - Added the [Item and Collection API Version extension](api-spec/extensions/version/README.md) to support versioning in the API specification
+    - Added the [Item and Collection API Version extension](api-spec/extensions/version/README.md) to support versioning in the API specification
 
 ### Changed
 - Support for [CommonMark 0.29 instead of CommonMark 0.28](https://spec.commonmark.org/0.29/changes.html)
 - Collection field `property` and the merge ability moved to a new extension 'Commons'
 - Added attribute `roles` to Item assets (also Asset definitions extension), to be used similarly to Link `rel`.
 - Updated API yaml to clarify bbox filter should be implemented without brackets. Example: `bbox=160.6,-55.95,-170,-25.89`
 - Collection `summaries` merge array fields now.
-
+- Several fields have been moved from extensions or item fields to the [Common Metadata fields](item-spec/common-metadata.md):
+    - `eo:platform` / `sar:platform` => `platform`
+    - `eo:instrument` / `sar:instrument` => `instruments`, also changed from string to array of strings
+    - `eo:constellation` / `sar:constellation` => `constellation`
+    - `dtr:start_datetime` => `start_datetime`
+    - `dtr:end_datetime` => `end_datetime`
 - Extensions:
-    - [datetime-range extension](extensions/datetime-range/README.md): Removed extension prefix from example and schema
     - Data Cube extension: Changed allowed formats (removed PROJ string, added PROJJSON / WKT2) for reference systems
     - [Checksum extension](extensions/checksum/README.md) is now using self-identifiable hashes ([Multihash](https://github.com/multiformats/multihash))
     - Changed `sar:type` to `sar:product_type` and `sar:polarization` to `sar:polarizations` in the [SAR extension](extensions/sar/README.md)
@@ -41,10 +45,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Removed `version` field in STAC Collections. Use [Version Extension](extensions/version/README.md) instead
 - Removed `summaries` field from Catalogs. Use Collections instead
 - Extensions:
-    - Removed `eo:platform`, `eo:instrument`, `eo:constellation` from EO extension, and `sar:platform`, `sar:instrument`, `sar:constellation` from the [SAR extension](extensions/sar/README.md)
+    - Removed `eo:platform`, `eo:instrument`, `eo:constellation` from EO extension, and `sar:platform`, `sar:instrument`, `sar:constellation` from the [SAR extension](extensions/sar/README.md).  Use the [Common Metadata fields](item-spec/common-metadata.md) instead.
     - Removed `sar:absolute_orbit` and `sar:center_wavelength` fields from the [SAR extension](extensions/sar/README.md)
     - Removed `data_type` and `unit` from the `sar:bands` object in the [SAR extension](extensions/sar/README.md)
-    - Removed `dtr` extension prefix from example and schema in [datetime-range extension](extensions/datetime-range/README.md)
+    - Removed Datetime Range (`dtr`) extension. Use the [Common Metadata fields](item-spec/common-metadata.md) instead.  
 - Asset Types (pre-defined values for the keys of individual assets, *not* media types) in Items. Use the asset's `roles` instead.
 - `license` field doesn't allow SPDX expressions any longer. Use `various` and links instead.
 - STAC API:

collection-spec/examples/landsat-item.json

@@ -3,7 +3,6 @@
     "stac_extensions": [
         "commons",
         "eo",
-        "instrument",
         "https://example.com/stac/landsat-extension/1.0/schema.json"
     ],
     "id": "LC08_L1TP_107018_20181001_20181001_01_RT",

collection-spec/json-schema/collection.json

@@ -54,7 +54,8 @@
         },
         "license": {
           "title": "Collection License Name",
-          "type": "string"
+          "type": "string",
+          "pattern": "^[\\w\\-\\.\\+]+$"
         },
         "providers": {
           "type": "array",
@@ -65,7 +66,7 @@
                 "type": "string"
               },
               "description": {
-                "title": "Provider description",
+                "title": "Organization description",
                 "type": "string"
               },
               "roles": {
@@ -82,7 +83,7 @@
                 }
               },
               "url": {
-                "title": "Homepage",
+                "title": "Organization homepage",
                 "type": "string",
                 "format": "url"
               }

extensions/README.md

@@ -51,9 +51,7 @@ An extension can add new fields to STAC entities (content extension), or can add
 | [Checksum](checksum/README.md) (`checksum`)                  | Item, Catalog, Collection | Provides a way to specify file checksums for assets and links in Items, Catalogs and Collections. | *Proposal* |
 | [Commons](commons/README.md) (-)                             | Item, Collection | Provides a way to specify data fields in a collection that are common across the STAC Items in that collection, so that each does not need to repeat all the same information. | *Proposal* |
 | [Data Cube](datacube/README.md) (`cube`)                     | Item, Collection | Data Cube related metadata, especially to describe their dimensions. | *Proposal* |
-| [Datetime Range](datetime-range/README.md) (-)               | Item             | An extension to provide datetime ranges with a start and an end datetime stamp in a consistent way. | *Proposal* |
 | [EO](eo/README.md) (`eo`)                                    | Item             | Covers electro-optical data that represents a snapshot of the earth for a single date and time. It could consist of multiple spectral bands, for example visible bands, infrared bands, red edge bands and panchromatic bands. The extension provides common fields like bands, cloud cover, gsd and more. | *Pilot* |
-| [Instrument](instrument/README.md) (-)                       | Item             | Adds metadata specifying a platform and instrument used in a data collection mission. | *Proposal* |
 | [Label](label/README.md) (`label`)                           | Item             | Items that relate labeled AOIs with source imagery | *Proposal* |
 | [Point Cloud](pointcloud/README.md) (`pc`)                   | Item             | Provides a way to describe point cloud datasets. The point clouds can come from either active or passive sensors, and data is frequently acquired using tools such as LiDAR or coincidence-matched imagery. | *Proposal* |
 | [SAR](sar/README.md) (`sar`)                                 | Item             | Covers synthetic-aperture radar data that represents a snapshot of the earth for a single date and time. | *Proposal* |

extensions/commons/README.md

@@ -76,7 +76,7 @@ An incomplete item:
 ```
 {
   "stac_version": "0.8.1",
-  "stac_extensions": ["commons", "eo", "instrument", "sat"],
+  "stac_extensions": ["commons", "eo", "sat"],
   "type": "Feature",
   "id": "LC08_L1TP_107018_20181001_20181001_01_RT",
   "bbox": [...],
@@ -98,7 +98,7 @@ The merged Item then looks like this:
 ```
 {
   "stac_version": "0.8.1",
-  "stac_extensions": ["eo", "instrument", "sat"],
+  "stac_extensions": ["eo", "sat"],
   "type": "Feature",
   "id": "LC08_L1TP_107018_20181001_20181001_01_RT",
   "bbox": [...],

extensions/commons/examples/landsat-item.json

@@ -3,7 +3,6 @@
     "stac_extensions": [
         "commons",
         "eo",
-        "instrument",
         "sat",
         "https://example.com/stac/landsat-extension/1.0/schema.json"
     ],

extensions/eo/README.md

@@ -18,7 +18,7 @@ A lot of EO data will have common metadata across many Items.
 It is not necessary, but recommended to use the [Commons extension](../commons/README.md)
 (see chapter "Placing common fields in Collections").
 
-If the data has been collected by a satellite, it is strongly recommended to use the [`sat` extension](../sat/README.md), which in turn requires the [`instrument` extension](../instrument/README.md). If the data has been collected on an airborne platform is is strongly recommended to use the [`instrument` extension](../instrument/README.md).
+If the data has been collected by a satellite, it is strongly recommended to use the [`sat` extension](../sat/README.md), which in turn requires the [Instrument Fields](../item-spec/common-metadata.md#instrument). If the data has been collected on an airborne platform is is strongly recommended to use the [Instrument Fields](../item-spec/common-metadata.md#instrument).
 
 - [Example (Landsat 8)](examples/example-landsat8.json)
 - [JSON Schema](json-schema/schema.json)
@@ -223,7 +223,6 @@ the eo:bands portion is still being fleshed out.
 The [extensions page](../README.md) gives an overview about related extensions. Of particular relevance to EO data:
 
 * the [Sat Extension Specification](../sat/README.md) to describe SAR data collected from a satellite.
-* the [Instrument Extension Specification](../instrument/README.md) is required when using the EO extension, which contains fields about the sensor and platform used to collect the data. It is required when using the Sat extension.
 
 ### Placing common fields in Collections
 A lot of EO data will have common metadata across many Items. It is not necessary, but recommended	

extensions/eo/examples/example-landsat8.json

@@ -2,7 +2,6 @@
     "stac_version": "0.9.0",
     "stac_extensions": [
       "eo",
-      "instrument",
       "https://example.com/stac/landsat-extension/1.0/schema.json"
     ],
     "id": "LC08_L1TP_107018_20181001_20181001_01_RT",