From 3e3c302e3ea9d5593d82ae7f437145dc2814740f Mon Sep 17 00:00:00 2001
From: Matthias Mohr <webmaster@mamo-net.de>
Date: Tue, 28 May 2024 17:58:53 +0200
Subject: [PATCH] Add classification:classes to SCL asset #165

---
 CHANGELOG.MD                    |  6 ++++++
 src/stactools/sentinel2/stac.py | 27 +++++++++++++++++++++------
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.MD b/CHANGELOG.MD
index fb7fa04..ccd8511 100644
--- a/CHANGELOG.MD
+++ b/CHANGELOG.MD
@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/). This project attempts to match the major and minor versions of [stactools](https://github.com/stac-utils/stactools) and increments the patch number as needed.
 
+## [Unreleased]
+
+### Added
+
+- Added a `classification:classes` field to the `scl` asset (SCL).
+
 ## [0.6.4] - 2024-04-04
 
 ### Added
diff --git a/src/stactools/sentinel2/stac.py b/src/stactools/sentinel2/stac.py
index 0d94262..5028127 100644
--- a/src/stactools/sentinel2/stac.py
+++ b/src/stactools/sentinel2/stac.py
@@ -11,6 +11,7 @@
 
 import antimeridian
 import pystac
+from pystac.extensions.classification import Classification, ClassificationExtension
 from pystac.extensions.eo import Band, EOExtension
 from pystac.extensions.grid import GridExtension
 from pystac.extensions.projection import ProjectionExtension
@@ -465,12 +466,26 @@ def set_asset_properties(_asset: pystac.Asset, _band_gsd: Optional[int] = None):
         asset_id = mk_asset_id(maybe_res, "scl")
         set_asset_properties(asset, maybe_res)
 
-        RasterExtension.ext(asset).bands = [
-            RasterBand.create(
-                nodata=0,
-                spatial_resolution=resolution,
-                data_type=DataType.UINT8,
-            )
+        band = RasterBand.create(
+            nodata=0,
+            spatial_resolution=resolution,
+            data_type=DataType.UINT8,
+        )
+        RasterExtension.ext(asset).bands = [band]
+
+        ClassificationExtension.ext(band).classes = [
+            Classification.create(0, "no_data"),
+            Classification.create(1, "saturated_or_defective"),
+            Classification.create(2, "dark_area_pixels"),
+            Classification.create(3, "cloud_shadows"),
+            Classification.create(4, "vegetation"),
+            Classification.create(5, "not_vegetated"),
+            Classification.create(6, "water"),
+            Classification.create(7, "unclassified"),
+            Classification.create(8, "cloud_medium_probability"),
+            Classification.create(9, "cloud_high_probability"),
+            Classification.create(10, "thin_cirrus"),
+            Classification.create(11, "snow"),
         ]
 
     elif CLD_PATTERN.search(asset_href):