Merge pull request #55 from developmentseed/feat/proj-wkt2

Add wkt2 proj info if available

CHANGES.md

@@ -1,4 +1,8 @@
 
+## 0.9.0 (2023-12-08)
+
+* add `wkt2` representation of the dataset CRS if available (author @emileten, https://github.com/developmentseed/rio-stac/pull/55)
+
 ## 0.8.1 (2023-09-27)
 
 * update `tests` requirements

rio_stac/stac.py

@@ -87,16 +87,37 @@ def get_projection_info(
 ) -> Dict:
     """Get projection metadata.
 
-    see: https://github.com/stac-extensions/projection/#item-properties-or-asset-fields
+    The STAC projection extension allows for three different ways to describe the coordinate reference system
+    associated with a raster :
+    - EPSG code
+    - WKT2
+    - PROJJSON
+
+    All are optional, and they can be provided altogether as well. Therefore, as long as one can be obtained from
+    the data, we add it to the returned dictionary.
+
+    see: https://github.com/stac-extensions/projection
 
     """
     projjson = None
+    wkt2 = None
     epsg = None
     if src_dst.crs is not None:
+        # EPSG
         epsg = src_dst.crs.to_epsg() if src_dst.crs.is_epsg_code else None
+
+        # PROJJSON
         try:
             projjson = src_dst.crs.to_dict(projjson=True)
-        except (AttributeError, TypeError):
+        except (AttributeError, TypeError) as ex:
+            warnings.warn(f"Could not get PROJJSON from dataset : {ex}")
+            pass
+
+        # WKT2
+        try:
+            wkt2 = src_dst.crs.to_wkt()
+        except Exception as ex:
+            warnings.warn(f"Could not get WKT2 from dataset : {ex}")
             pass
 
     meta = {
@@ -106,12 +127,13 @@ def get_projection_info(
         "shape": [src_dst.height, src_dst.width],
         "transform": list(src_dst.transform),
     }
+
     if projjson is not None:
         meta["projjson"] = projjson
-    # rasterio can't reproduce wkt2
-    # ref: https://github.com/mapbox/rasterio/issues/2044
-    # if epsg is None:
-    #      meta["wkt2"] = src_dst.crs.to_wkt()
+
+    if wkt2 is not None:
+        meta["wkt2"] = wkt2
+
     return meta
 
 

tests/test_create_item.py

@@ -115,6 +115,8 @@ def test_create_item_options():
     ]
     assert "datetime" in item_dict["properties"]
     assert "proj:epsg" in item_dict["properties"]
+    assert "proj:wkt2" in item_dict["properties"]
+    assert "proj:projjson" in item_dict["properties"]
     assert "sci:citation" in item_dict["properties"]
 
     # external assets