diff --git a/xvec/accessor.py b/xvec/accessor.py
index d63edeb..2aacc70 100644
--- a/xvec/accessor.py
+++ b/xvec/accessor.py
@@ -658,7 +658,8 @@ def mask(
         xr.DataArray
             A DataArray with the same shape as the original, where the elements matching the predicate are set to True.
         """
-        cube_data = self._obj.data.ravel()
+        # need to replace nan with None
+        cube_data = self._obj.where(~self._obj.isnull(), None).data.ravel()
         tree = shapely.STRtree(cube_data)
         indices = tree.query(geometry, predicate=predicate, distance=distance)
         if indices.ndim == 1:
diff --git a/xvec/zonal.py b/xvec/zonal.py
index 2a7b384..32eed1a 100644
--- a/xvec/zonal.py
+++ b/xvec/zonal.py
@@ -581,17 +581,22 @@ def _get_mean(
 ):
     from rasterio import features
 
-    mask = features.geometry_mask(
-        [geom_arr.item()],
-        out_shape=(
-            obj[y_coords].shape[0],
-            obj[x_coords].shape[0],
-        ),
-        transform=transform,
-        invert=True,
-        all_touched=all_touched,
-    )
-    masked = obj.where(xr.DataArray(mask, dims=(y_coords, x_coords)))
+    if pd.isna(geom_arr.item()):
+        masked = obj.where(
+            xr.DataArray(np.full_like(obj.data, False), dims=(y_coords, x_coords))
+        )
+    else:
+        mask = features.geometry_mask(
+            [geom_arr.item()],
+            out_shape=(
+                obj[y_coords].shape[0],
+                obj[x_coords].shape[0],
+            ),
+            transform=transform,
+            invert=True,
+            all_touched=all_touched,
+        )
+        masked = obj.where(xr.DataArray(mask, dims=(y_coords, x_coords)))
 
     if nodata is not None:
         masked = masked.where(masked != nodata)