Add default value in vectorize when dataarray has no name, and a warn…

…ing (#166)

geocube/vector.py

@@ -1,6 +1,8 @@
 """
 Module for vector methods
 """
+import warnings
+
 import geopandas
 import numpy
 import rasterio.features
@@ -53,8 +55,15 @@ def vectorize(data_array: xarray.DataArray) -> geopandas.GeoDataFrame:
             mask=mask,
         )
     )
+
+    if data_array.name:
+        name = data_array.name
+    else:
+        warnings.warn("The array has no name. Column name defaults to _data")
+        name = "_data"
+
     return geopandas.GeoDataFrame(
         vectorized_data,
-        columns=[data_array.name, "geometry"],
+        columns=[name, "geometry"],
         crs=data_array.rio.crs,
     )

test/integration/test_vector.py

@@ -43,3 +43,18 @@ def test_vectorize__missing_nodata():
     assert not gdf.geometry.isnull().any()
     assert not gdf.om_r.isnull().any()
     assert len(gdf.index) == 8
+
+
+def test_vectorize__no_name():
+    xds = xarray.open_dataset(
+        TEST_COMPARE_DATA_DIR / "soil_grid_flat.nc",
+        decode_coords="all",
+        mask_and_scale=False,
+    )
+
+    test_array = xarray.DataArray(xds.om_r.data)
+
+    with pytest.warns(UserWarning):
+        gdf = vectorize(test_array)
+
+    assert "_data" in gdf.columns