Revert altimetry changes (#25)

Author: m-mohr

CHANGELOG.md

@@ -12,17 +12,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Added `LH`, `LV`, `RH`, `RV`, `CH` and `CV` enumerations to `sar:polarizations` to support compact polarization.
-- Best practices for `altm:instrument_mode` and `altm:instrument_type`
 
 ### Changed
 
 - Required fields are recommended.
 - Clarified the scope of the fields.
 
-### Deprecated
-
-- `sar:instrument_mode` in favor of `altm:instrument_mode`
-
 ### Fixed
 
 - Fixed and updated examples

README.md

@@ -18,8 +18,6 @@ If the data has been collected by a satellite, it is recommended to use the
 [Satellite extension](https://github.com/stac-extensions/sat).
 If the data has been collected on an airborne platform it is recommended to use the
 [Instrument Fields](https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md#instrument).
-In both cases the instrument details should be provided using the
-[Altimetry extension](https://github.com/stac-extensions/altimetry)
 
 To describe frame start and end times, use the
 [Date and Time Range fields](https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md#date-and-time-range).
@@ -52,6 +50,7 @@ The fields in the table below can be used in these parts of STAC documents:
 | Field Name                  | Type      | Description |
 | --------------------------- | --------- | ----------- |
 | sar:polarizations           | \[string] | RECOMMENDED. Any combination of polarizations. |
+| sar:instrument_mode         | string    | RECOMMENDED. The name of the sensor acquisition mode that is commonly used. This should be the short name, if available. For example, `WV` for "Wave mode" of Sentinel-1 and Envisat ASAR satellites. |
 | sar:frequency_band          | string    | RECOMMENDED. The common name for the frequency band to make it easier to search for bands across instruments. See section "Common Frequency Band Names" for a list of accepted names. |
 | sar:center_frequency        | number    | RECOMMENDED. The center frequency of the instrument, in gigahertz (GHz). |
 | sar:resolution_range        | number    | The range resolution, which is the maximum ability to distinguish two adjacent targets perpendicular to the flight path, in meters (m). |
@@ -65,16 +64,13 @@ The fields in the table below can be used in these parts of STAC documents:
 | sar:relative_burst          | number    | Identification number that uniquely identifies a burst cycle within each repeat cycle. |
 | sar:beam_ids                | \[string] | Composition of the swath of the SAR acquision referencing the beam identifiers. |
 | sar:product_type            | string    | ***DEPRECATED** in favor of [`product:type`](https://github.com/stac-extensions/product).* See [Product type](#product-type). |
-| sar:instrument_mode         | string    | ***DEPRECATED** in favor of [`altm:instrument_mode`](https://github.com/stac-extensions/altimetry).* See [Instrument details](#instrument-details). |
 
 > \[!CAUTION]  
 >
-> - v1.0 of the extension did require `sar:product_type` and `sar:instrument_mode`.
+> - v1.0 of the extension did require `sar:product_type`.
 > - v1.1 deprecates `sar:product_type` and it's not required any longer, but
 >   [`product:type`](https://github.com/stac-extensions/product) is **strongly recommended**.
-> - v1.2 deprecates `sar:instrument_mode` and it's not required any longer, but
->   [`altm:instrument_mode` and `altm:instrument_type`](https://github.com/stac-extensions/altimetry) are **strongly recommended**.
-> - v2.0 is going to remove `sar:product_type` and `sar:instrument_mode`.
+> - v2.0 is going to remove `sar:product_type`.
 
 ### Additional Field Information
 
@@ -134,15 +130,6 @@ A list of suggestions for [`product:type`](https://github.com/stac-extensions/pr
 This can vary by data provider, who all may use slightly different names.
 Sentinel-1 for instance uses `GRD`, which is the same as the more general `MGD` and `SLC` instead of `SGC`.
 
-### Instrument details
-
-The instrument type and mode can be provided using the [Altimetry Extension](https://github.com/stac-extensions/altimetry):
-
-- `altm:instrument_type`: RECOMMENDED. The instrument type, must be set to `sar`,
-- `altm:instrument_mode`: RECOMMENDED. The name of the sensor acquisition mode that is commonly used.
-  This should be the short name, if available.
-  For example, `WV` for "Wave mode" of Sentinel-1 and Envisat ASAR satellites.
-
 ### Date and Time
 
 In SAR, you usually have frame start and end time. To describe this information it is recommended to use the [Date and Time Range fields](https://github.com/radiantearth/stac-spec/blob/master/item-spec/common-metadata.md#date-and-time-range).

examples/envisat.json

@@ -3,7 +3,6 @@
   "stac_version": "1.0.0",
   "stac_extensions": [
     "https://stac-extensions.github.io/sar/v1.2.0/schema.json",
-    "https://stac-extensions.github.io/altimetry/v0.1.0/schema.json",
     "https://stac-extensions.github.io/product/v0.1.0/schema.json"
   ],
   "id": "sar-envisat-example",
@@ -27,8 +26,7 @@
     "sar:looks_azimuth": 4,
     "sar:frequency_band": "C",
     "sar:center_frequency": 5.331,
-    "altm:instrument_type": "sar",
-    "altm:instrument_mode": "GM",
+    "sar:instrument_mode": "GM",
     "product:type": "GM1_1P"
   },
   "geometry": {

examples/sentinel-1-grd-ew.json

@@ -3,7 +3,6 @@
   "stac_version": "1.0.0",
   "stac_extensions": [
     "https://stac-extensions.github.io/sar/v1.2.0/schema.json",
-    "https://stac-extensions.github.io/altimetry/v0.1.0/schema.json",
     "https://stac-extensions.github.io/product/v0.1.0/schema.json"
   ],
   "id": "sentinel-1-example",
@@ -31,8 +30,7 @@
     "sar:beam_ids": [
       "EW"
     ],
-    "altm:instrument_type": "sar",
-    "altm:instrument_mode": "EW",
+    "sar:instrument_mode": "EW",
     "product:type": "GRD"
   },
   "geometry": {

examples/sentinel-1-grd-s4.json

@@ -3,7 +3,6 @@
   "stac_version": "1.0.0",
   "stac_extensions": [
     "https://stac-extensions.github.io/sar/v1.2.0/schema.json",
-    "https://stac-extensions.github.io/altimetry/v0.1.0/schema.json",
     "https://stac-extensions.github.io/processing/v1.2.0/schema.json",
     "https://stac-extensions.github.io/product/v0.1.0/schema.json",
     "https://stac-extensions.github.io/sat/v1.0.0/schema.json"
@@ -52,8 +51,7 @@
     "instruments": [
       "SAR"
     ],
-    "altm:instrument_type": "sar",
-    "altm:instrument_mode": "SM",
+    "sar:instrument_mode": "SM",
     "processing:datetime": "2024-05-31T11:25:04.541000Z",
     "processing:level": "L1",
     "processing:facility": "Production Service-SERCO",

examples/sentinel-1-slc-iw.json

@@ -4,7 +4,6 @@
   "stac_extensions": [
     "https://stac-extensions.github.io/sar/v1.2.0/schema.json",
     "https://stac-extensions.github.io/alternate-assets/v1.1.0/schema.json",
-    "https://stac-extensions.github.io/altimetry/v0.1.0/schema.json",
     "https://stac-extensions.github.io/storage/v1.0.0/schema.json"
   ],
   "id": "S1A_IW_SLC__1SDV_20240618T173936_20240618T174003_054381_069DC0_C1A4.SAFE",
@@ -45,8 +44,7 @@
     "datetime": "2024-06-18T17:39:36.336Z",
     "end_datetime": "2024-06-18T17:40:03.297Z",
     "start_datetime": "2024-06-18T17:39:36.336Z",
-    "altm:instrument_type": "sar",
-    "altm:instrument_mode": "IW",
+    "sar:instrument_mode": "IW",
     "processing:datetime": "2024-06-18T18:24:17.837861Z",
     "processing:level": "L1",
     "processing:facility": "Production Service-SERCO",