add via_cf_namespace option

pyproject.toml

@@ -9,6 +9,7 @@ author-email = "taugspurger@microsoft.com"
 classifiers = [ "License :: OSI Approved :: MIT License",]
 requires = [
     "xarray",
+    "cf_xarray",
     "numpy",
     "pystac>=1.0.0b3",
     "pandas",

test_xstac.py

@@ -117,7 +117,8 @@ def ds():
     return fix_attrs(ds)
 
 
-def test_xarray_to_stac(ds):
+@pytest.mark.parametrize("via_cf_namespace", [False, True])
+def test_xarray_to_stac(ds, via_cf_namespace):
     template = {
         "id": "id",
         "type": "Collection",
@@ -132,6 +133,7 @@ def test_xarray_to_stac(ds):
         temporal_dimension="time",
         x_dimension="x",
         y_dimension="y",
+        via_cf_namespace=via_cf_namespace,
     )
     assert result.id == "id"
     assert isinstance(result, pystac.Collection)
@@ -457,7 +459,8 @@ def test_validation_with_none():
     c.validate()
 
 
-def test_xarray_to_stac_item(ds):
+@pytest.mark.parametrize("via_cf_namespace", [False, True])
+def test_xarray_to_stac_item(ds, via_cf_namespace):
     template = {
         "id": "id",
         "type": "Feature",
@@ -473,6 +476,7 @@ def test_xarray_to_stac_item(ds):
         temporal_dimension="time",
         x_dimension="x",
         y_dimension="y",
+        via_cf_namespace=via_cf_namespace,
     )
     assert result.id == "id"
     assert isinstance(result, pystac.Item)

xstac/_xstac.py

@@ -4,6 +4,7 @@
 import copy
 import json
 from pystac import stac_object
+import cf_xarray  # adds `.cf` namespace to xarray datasets
 import xarray as xr
 import numpy as np
 import pystac
@@ -72,8 +73,10 @@ def maybe_infer_step(da, step):
     return step
 
 
-def build_temporal_dimension(ds, name, extent, values, step):
-    time = ds.coords[name]
+def build_temporal_dimension(
+    ds, name, extent, values, step, via_cf_namespace: bool = False
+):
+    time = ds.coords[name] if not via_cf_namespace else ds.cf[name]
     extent = (
         pd.to_datetime(
             np.concatenate([time.min(keepdims=True), time.max(keepdims=True)])
@@ -103,8 +106,17 @@ def build_temporal_dimension(ds, name, extent, values, step):
     )
 
 
-def build_horizontal_dimension(ds, name, axis, extent, values, step, reference_system):
-    da = ds[name]
+def build_horizontal_dimension(
+    ds,
+    name,
+    axis,
+    extent,
+    values,
+    step,
+    reference_system,
+    via_cf_namespace: bool = False,
+):
+    da = ds[name] if not via_cf_namespace else ds.cf[name]
     if extent is None:
         extent = np.asarray(
             np.concatenate([da.min(keepdims=True), da.max(keepdims=True)])
@@ -215,13 +227,19 @@ def build_datacube(
     vertical_extent=None,
     vertical_values=None,
     vertical_step=None,
+    via_cf_namespace: bool = False,
     **additional_dimensions,
 ):
     dimensions = {}
 
     if temporal_dimension is not None:
         dimensions[temporal_dimension] = build_temporal_dimension(
-            ds, temporal_dimension, temporal_extent, temporal_values, temporal_step
+            ds,
+            temporal_dimension,
+            temporal_extent,
+            temporal_values,
+            temporal_step,
+            via_cf_namespace=via_cf_namespace,
         )
 
     if x_dimension:
@@ -233,6 +251,7 @@ def build_datacube(
             x_values,
             x_step,
             reference_system=reference_system,
+            via_cf_namespace=via_cf_namespace,
         )
     if y_dimension:
         dimensions[y_dimension] = build_horizontal_dimension(
@@ -243,6 +262,7 @@ def build_datacube(
             y_values,
             y_step,
             reference_system=reference_system,
+            via_cf_namespace=via_cf_namespace,
         )
 
     if vertical_dimension:
@@ -288,6 +308,7 @@ def xarray_to_stac(
     vertical_values=None,
     vertical_step=None,
     validate: bool = True,
+    via_cf_namespace: bool = False,
     **additional_dimensions,
 ) -> pystac.Collection:
     """
@@ -328,6 +349,7 @@ def xarray_to_stac(
         vertical_extent=vertical_extent,
         vertical_values=vertical_values,
         vertical_step=vertical_step,
+        via_cf_namespace=via_cf_namespace,
         **additional_dimensions,
     )