Add processing:datastrip_id

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The fields can be used in Provider Objects in Item Properties and Assets
 - The JSON Schema validates the fields in Collection summaries
 - Relation type `source_for` for forward provenance (inverse of `derived_from`)
+- `processing:datastrip_id` to identify the part of a datatake that the ground segment processed as one unit
 
 ### Changed
 

README.md

@@ -19,6 +19,7 @@ and therefore are shared across all items, it is recommended adding the fields t
 - Examples:
   - [Item example](examples/item.json): Shows the basic usage of the extension in a STAC Item
   - [Collection example](examples/collection.json): Shows the basic usage of the extension in a STAC Collection
+  - [Sentinel-2 Item example](examples/item-sentinel-2.json): Shows the datastrip identifier in a STAC Item
 - [JSON Schema](json-schema/schema.json)
 - [Changelog](./CHANGELOG.md)
 
@@ -44,6 +45,7 @@ The fields in the table below can be used in these parts of STAC documents:
 | processing:datetime     | string              | Processing date and time of the corresponding data formatted according to [RFC 3339, section 5.6](https://tools.ietf.org/html/rfc3339#section-5.6), in UTC. |
 | processing:version      | string              | The version of the primary processing software or processing chain that produced the data. For example, this could be the processing baseline for the Sentinel missions. |
 | processing:software     | Map<string, string> | A dictionary with name/version for key/value describing one or more applications or libraries that were involved during the production of the data for provenance purposes. |
+| processing:datastrip_id | string              | The identifier of the datastrip, i.e. the part of a datatake that the ground segment processed as one unit. See [Datastrip ID](#datastrip-id) for details. |
 
 In more detail, the following restrictions apply:
 
@@ -93,6 +95,29 @@ In Item Properties:
   If you need more information, you could also link to such files via the relation type `processing-software`.
 - `version` is usually not used in the context of processing and describes the version of the metadata.
 
+### Datastrip ID
+
+A datatake is one continuous acquisition by an instrument in one mode.
+Some ground segments don't process a datatake as a whole.
+Instead, they process parts of it independently, e.g. the parts that different ground stations received.
+Sentinel-2 calls such a part a *datastrip*, and Landsat 7 calls it a *subinterval*.
+`processing:datastrip_id` gives the identifier of the datastrip that the data was produced from.
+
+The value is an opaque string.
+Use the identifier as given by the provider and don't change its format.
+Some providers assign new datastrip identifiers for each processing level or processing run.
+Thus Items of the same acquisition at different processing levels may have different values.
+
+For the identifier of the datatake itself, use `instrument:datatake_id` from the
+[Instruments extension](https://github.com/stac-extensions/instruments).
+If the ground segment processes the datatake as a whole, don't provide `processing:datastrip_id`.
+Note that some providers (e.g. Airbus for Pléiades) use the term *data strip* for the whole acquisition.
+Such identifiers are datatake identifiers and should be provided in `instrument:datatake_id` instead.
+
+If the data of an Item comes from more than one datastrip, don't provide this field in the Item properties.
+Instead, provide it in the Assets if each Asset comes from a single datastrip.
+Collections should not summarize this field.
+
 ### Linking the Items
 
 In Items that declare this processing extension, it is recommended to add one or more

examples/item-sentinel-2.json

@@ -0,0 +1,64 @@
+{
+  "stac_version": "1.1.0",
+  "stac_extensions": [
+    "https://stac-extensions.github.io/processing/v1.2.0/schema.json"
+  ],
+  "type": "Feature",
+  "id": "S2A_MSIL2A_20250626T101701_R065_T32UQU_20250626T142217",
+  "bbox": [
+    11.667,
+    47.72,
+    12.586,
+    48.721
+  ],
+  "geometry": {
+    "type": "Polygon",
+    "coordinates": [
+      [
+        [
+          11.667,
+          47.72
+        ],
+        [
+          12.586,
+          47.72
+        ],
+        [
+          12.586,
+          48.721
+        ],
+        [
+          11.667,
+          48.721
+        ],
+        [
+          11.667,
+          47.72
+        ]
+      ]
+    ]
+  },
+  "properties": {
+    "datetime": "2025-06-26T10:17:01.024Z",
+    "constellation": "sentinel-2",
+    "platform": "sentinel-2a",
+    "instruments": [
+      "msi"
+    ],
+    "processing:level": "L2",
+    "processing:version": "05.11",
+    "processing:datetime": "2025-06-26T14:22:17Z",
+    "processing:datastrip_id": "S2A_OPER_MSI_L2A_DS_2APS_20250626T142217_S20250626T102649_N05.11"
+  },
+  "links": [
+    {
+      "href": "https://example.com/examples/item-sentinel-2.json",
+      "rel": "self"
+    }
+  ],
+  "assets": {
+    "data": {
+      "href": "https://example.com/examples/file.xyz"
+    }
+  }
+}

json-schema/schema.json

@@ -155,6 +155,14 @@
         }
       ]
     },
+    "processing:datastrip_id": {
+      "title": "Datastrip ID",
+      "type": "string",
+      "minLength": 1,
+      "examples": [
+        "S2A_OPER_MSI_L2A_DS_2APS_20250626T142217_S20250626T102649_N05.11"
+      ]
+    },
     "fields": {
       "$comment": "Don't require fields here as they would be required in all places where the fields are referenced.",
       "type": "object",
@@ -179,6 +187,9 @@
         },
         "processing:software": {
           "$ref": "#/definitions/processing:software"
+        },
+        "processing:datastrip_id": {
+          "$ref": "#/definitions/processing:datastrip_id"
         }
       },
       "patternProperties": {
@@ -275,6 +286,12 @@
           "items": {
             "$ref": "#/definitions/processing:software"
           }
+        },
+        "processing:datastrip_id": {
+          "type": ["array", "object"],
+          "items": {
+            "$ref": "#/definitions/processing:datastrip_id"
+          }
         }
       },
       "patternProperties": {