id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type 1168304665,I_kwDOAMm_X85FouoZ,6355,ValueError: Resulting object does not have monotonic global indexes along dimension in combine_by_coords call ,24227838,open,0,,,2,2022-03-14T12:25:18Z,2022-03-16T15:42:06Z,,NONE,,,,"### What happened? When I try to do a `combine_by_coords` on 2 datasets x, y like ```python x1 = xr.Dataset( { ""temperature"": ((""y"", ""x""), 20 * np.random.rand(6).reshape(2, 3)), ""precipitation"": ((""y"", ""x""), np.random.rand(6).reshape(2, 3)), }, coords={""y"": [0, 1], ""x"": [20, 30, 40]}, ) x2 = xr.Dataset( { ""temperature"": ((""y"", ""x""), 20 * np.random.rand(6).reshape(2, 3)), ""precipitation"": ((""y"", ""x""), np.random.rand(6).reshape(2, 3)), }, coords={""y"": [2, 3], ""x"": [10, 20, 30]}, ) ``` `x1` looks like: ```shell 1| x x x 0| x x x ---------------- 20 30 40 ``` `x2` Looks like: ```shell 3| y y y 2| y y y -------------- 10 20 30 ``` I have this issue after a ```python ds_test = xr.combine_by_coords([x2, x1]) ``` ```python ValueError: Resulting object does not have monotonic global indexes along dimension x ``` ### What did you expect to happen? For me the result of `ds_test` should be like: ```shell 3| y y y 2| y y y 1| x x x 0| x x x ---------------- 10 20 30 40 ``` ### Minimal Complete Verifiable Example ```Python import numpy as np import xarray as xr print(xr.__version__) x1 = xr.Dataset( { ""temperature"": ((""y"", ""x""), 20 * np.random.rand(6).reshape(2, 3)), ""precipitation"": ((""y"", ""x""), np.random.rand(6).reshape(2, 3)), }, coords={""y"": [0, 1], ""x"": [20, 30, 40]}, ) x2 = xr.Dataset( { ""temperature"": ((""y"", ""x""), 20 * np.random.rand(6).reshape(2, 3)), ""precipitation"": ((""y"", ""x""), np.random.rand(6).reshape(2, 3)), }, coords={""y"": [2, 3], ""x"": [10, 20, 30]}, ) print(x1) print(x2) ds_test = xr.combine_by_coords([x2, x1]) ``` ### Relevant log output ```Python ValueError Traceback (most recent call last) /home/thomas/Work/internal-applications/sungeodata/app-sungeodata/test copy.ipynb Cell 6' in () ----> 1 ds_test = xr.combine_by_coords([x2, x1]) File ~/Work/internal-applications/sungeodata/app-sungeodata/.venv/lib/python3.8/site-packages/xarray/core/combine.py:979, in combine_by_coords(data_objects, compat, data_vars, coords, fill_value, join, combine_attrs, datasets) 977 concatenated_grouped_by_data_vars = [] 978 for vars, datasets_with_same_vars in grouped_by_vars: --> 979 concatenated = _combine_single_variable_hypercube( 980 list(datasets_with_same_vars), 981 fill_value=fill_value, 982 data_vars=data_vars, 983 coords=coords, 984 compat=compat, 985 join=join, 986 combine_attrs=combine_attrs, 987 ) 988 concatenated_grouped_by_data_vars.append(concatenated) 990 return merge( 991 concatenated_grouped_by_data_vars, 992 compat=compat, (...) 995 combine_attrs=combine_attrs, 996 ) File ~/Work/internal-applications/sungeodata/app-sungeodata/.venv/lib/python3.8/site-packages/xarray/core/combine.py:653, in _combine_single_variable_hypercube(datasets, fill_value, data_vars, coords, compat, join, combine_attrs) 651 indexes = concatenated.indexes.get(dim) 652 if not (indexes.is_monotonic_increasing or indexes.is_monotonic_decreasing): --> 653 raise ValueError( 654 f""Resulting object does not have monotonic"" 655 f"" global indexes along dimension {dim}"" 659 ) 661 return concatenated ValueError: Resulting object does not have monotonic global indexes along dimension x I add more logs with: ```python --------------------------------------------------------------------------- ValueError Traceback (most recent call last) /home/thomas/Work/internal-applications/sungeodata/app-sungeodata/test copy.ipynb Cell 6' in () ----> 1 ds_test = xr.combine_by_coords([x2, x1]) File ~/Work/internal-applications/sungeodata/app-sungeodata/.venv/lib/python3.8/site-packages/xarray/core/combine.py:979, in combine_by_coords(data_objects, compat, data_vars, coords, fill_value, join, combine_attrs, datasets) 977 concatenated_grouped_by_data_vars = [] 978 for vars, datasets_with_same_vars in grouped_by_vars: --> 979 concatenated = _combine_single_variable_hypercube( 980 list(datasets_with_same_vars), 981 fill_value=fill_value, 982 data_vars=data_vars, 983 coords=coords, 984 compat=compat, 985 join=join, 986 combine_attrs=combine_attrs, 987 ) 988 concatenated_grouped_by_data_vars.append(concatenated) 990 return merge( 991 concatenated_grouped_by_data_vars, 992 compat=compat, (...) 995 combine_attrs=combine_attrs, 996 ) File ~/Work/internal-applications/sungeodata/app-sungeodata/.venv/lib/python3.8/site-packages/xarray/core/combine.py:653, in _combine_single_variable_hypercube(datasets, fill_value, data_vars, coords, compat, join, combine_attrs) 651 indexes = concatenated.indexes.get(dim) 652 if not (indexes.is_monotonic_increasing or indexes.is_monotonic_decreasing): --> 653 raise ValueError( 654 f""Resulting object does not have monotonic"" 655 f"" global indexes along dimension {dim} \n"" 656 f"" indexes.is_monotonic_increasing {indexes.is_monotonic_increasing}"" 657 f"" indexes.is_monotonic_decreasing {indexes.is_monotonic_decreasing}\n"" 658 f"" concatenated[{dim}].values {concatenated[dim].values.tolist()}"" 659 ) 661 return concatenated ValueError: Resulting object does not have monotonic global indexes along dimension x indexes.is_monotonic_increasing False indexes.is_monotonic_decreasing False concatenated[x].values [10, 20, 30, 20, 30, 40] ``` ``` ### Anything else we need to know? _No response_ ### Environment INSTALLED VERSIONS ------------------ commit: None python: 3.8.10 (default, Nov 26 2021, 20:14:08) [GCC 9.3.0] python-bits: 64 OS: Linux OS-release: 5.13.0-30-generic machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: ('en_US', 'UTF-8') libhdf5: 1.12.0 libnetcdf: 4.7.4 xarray: 2022.3.0 pandas: 1.4.1 numpy: 1.22.3 scipy: 1.6.2 netCDF4: 1.5.5.1 pydap: None h5netcdf: None h5py: None Nio: None zarr: None cftime: 1.6.0 nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: 0.9.8.4 iris: None bottleneck: None dask: 2022.02.1 distributed: 2022.2.1 matplotlib: 3.4.3 cartopy: None seaborn: None numbagg: None fsspec: 2022.02.0 cupy: None pint: None sparse: None setuptools: 44.0.0 pip: 20.0.2 conda: None pytest: 7.0.1 IPython: 8.1.1 sphinx: 3.5.4","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/6355/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,issue