From 5f74c77a13b72d1235b57bf239a34cc9c973ca93 Mon Sep 17 00:00:00 2001
From: malmans2 <m.almansi@bopen.eu>
Date: Wed, 21 Jan 2026 18:03:03 +0100
Subject: [PATCH] add ignore_spatial_coords argument

---
 tests/test_20_open_dataset.py | 37 +++++++++++++++++++++++++++++++++++
 xarray_esgf/client.py         | 12 ++++++++++++
 xarray_esgf/engine.py         |  3 +++
 3 files changed, 52 insertions(+)

diff --git a/tests/test_20_open_dataset.py b/tests/test_20_open_dataset.py
index 2c14e0f..b249153 100644
--- a/tests/test_20_open_dataset.py
+++ b/tests/test_20_open_dataset.py
@@ -1,9 +1,13 @@
+import contextlib
 from collections.abc import Hashable
 from pathlib import Path
 from typing import Any
 
 import pytest
 import xarray as xr
+from xarray import AlignmentError
+
+does_not_raise = contextlib.nullcontext
 
 
 @pytest.mark.parametrize("download", [True, False])
@@ -142,3 +146,36 @@ def test_time_selection(
         sel=sel,
     )
     assert ds.sizes["time"] == expected_size
+
+
+@pytest.mark.parametrize(
+    "ignore_spatial_coords, raises",
+    [
+        ("areacella", does_not_raise()),
+        (None, pytest.raises(AlignmentError)),
+    ],
+)
+def test_ignore_spatial_coords(
+    tmp_path: Path,
+    index_node: str,
+    ignore_spatial_coords: str | None,
+    raises: contextlib.nullcontext,
+) -> None:
+    esgpull_path = tmp_path / "esgpull"
+    selection = {
+        "query": [
+            '"CMIP6.CMIP.MPI-M.MPI-ESM1-2-HR.historical.r1i1p1f1.fx.areacella.gn.v20190710.areacella_fx_MPI-ESM1-2-HR_historical_r1i1p1f1_gn.nc"',
+            '"CMIP6.CMIP.MPI-M.MPI-ESM1-2-HR.historical.r1i1p1f1.Amon.tas.gn.v20190710.tas_Amon_MPI-ESM1-2-HR_historical_r1i1p1f1_gn_185001-185412.nc"',
+        ]
+    }
+
+    with raises:
+        ds = xr.open_dataset(
+            selection,  # type: ignore[arg-type]
+            esgpull_path=esgpull_path,
+            engine="esgf",
+            index_node=index_node,
+            chunks={},
+            ignore_spatial_coords=ignore_spatial_coords,
+        )
+        assert {"lat", "lon"} <= set(ds.variables)
diff --git a/xarray_esgf/client.py b/xarray_esgf/client.py
index c6367ab..fe29d30 100644
--- a/xarray_esgf/client.py
+++ b/xarray_esgf/client.py
@@ -139,6 +139,7 @@ def _open_datasets(
         download: bool,
         show_progress: bool,
         sel: dict[Hashable, Any],
+        ignore_spatial_coords: str | Iterable[str],
     ) -> dict[str, Dataset]:
         sel = {
             k: slice(*v["slice"]) if isinstance(v, dict) else v for k, v in sel.items()
@@ -148,6 +149,10 @@ def _open_datasets(
             concat_dims = [concat_dims]
         concat_dims = concat_dims or []
 
+        if isinstance(ignore_spatial_coords, str):
+            ignore_spatial_coords = {ignore_spatial_coords}
+        ignore_spatial_coords = set(ignore_spatial_coords)
+
         if download:
             self.download()
 
@@ -162,7 +167,12 @@ def _open_datasets(
                 drop_variables=drop_variables,
                 storage_options={"ssl": self.verify_ssl},
             )
+
             ds = ds.sel({k: v for k, v in sel.items() if k in ds.dims})
+
+            if ignore_spatial_coords.intersection(ds.variables):
+                ds = ds.drop_vars(set(ds.variables) & {"lat", "lon"})
+
             if all(ds.sizes.values()):
                 grouped_objects[file.dataset_id].append(ds.drop_encoding())
 
@@ -192,6 +202,7 @@ def open_dataset(
         download: bool = False,
         show_progress: bool = True,
         sel: dict[Hashable, Any] | None = None,
+        ignore_spatial_coords: str | Iterable[str] | None = None,
     ) -> Dataset:
         combined_datasets = self._open_datasets(
             concat_dims=concat_dims,
@@ -199,6 +210,7 @@ def open_dataset(
             download=download,
             show_progress=show_progress,
             sel=sel or {},
+            ignore_spatial_coords=ignore_spatial_coords or {},
         )
 
         obj = combine_datasets([ds.reset_coords() for ds in combined_datasets.values()])
diff --git a/xarray_esgf/engine.py b/xarray_esgf/engine.py
index 4dab023..560c7a1 100644
--- a/xarray_esgf/engine.py
+++ b/xarray_esgf/engine.py
@@ -23,6 +23,7 @@ def open_dataset(  # type: ignore[override]
         download: bool = False,
         show_progress: bool = True,
         sel: dict[Hashable, Any] | None = None,
+        ignore_spatial_coords: str | Iterable[str] | None = None,
     ) -> Dataset:
         client = Client(
             selection=filename_or_obj,
@@ -38,6 +39,7 @@ def open_dataset(  # type: ignore[override]
             download=download,
             show_progress=show_progress,
             sel=sel,
+            ignore_spatial_coords=ignore_spatial_coords,
         )
 
     open_dataset_parameters = (
@@ -51,6 +53,7 @@ def open_dataset(  # type: ignore[override]
         "download",
         "show_progress",
         "sel",
+        "ignore_spatial_coords",
     )
 
     def guess_can_open(self, filename_or_obj: Any) -> bool: