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
654150730,MDU6SXNzdWU2NTQxNTA3MzA=,4213,Xarray combine_by_coords return the monotonic global index error,5567953,closed,0,,,10,2020-07-09T15:26:42Z,2023-03-03T07:07:31Z,2023-03-03T07:07:31Z,NONE,,,,"I asked this question on [Stackoverflow](https://stackoverflow.com/questions/62806175/xarray-combine-by-coords-return-the-monotonic-global-index-error) and someone mentioned it might be a bug.

I am trying to combine two spatial xarray datasets using combine_by_coords. These two datasets are two tiles next to each other. So there are overlapping coordinates. In the overlapping regions, the variable values of one of the datasets is nan.

I used the ""combine_by_coords"" with compat='no_conflicts' option. However, it returns the monotonic global indexes along dimension y error. It looks like it was an issue before but it was fixed ([issue 3150](https://github.com/pydata/xarray/issues/3150)). So I don't really know why I get this error. Here is an example (the netcdf tiles are [here](https://drive.google.com/file/d/12Eon5yUiuhKCaDF0YK-l-S0JYGNN6eNg/view?)): 
```
import xarray as xr

print(xr.__version__)
>>>0.15.1

ds1=xr.open_dataset('Tile1.nc')
ds2=xr.open_dataset('Tile2.nc')
ds = xr.combine_by_coords([ds1,ds2], compat='no_conflicts')
>>>...
 ValueError: Resulting object does not have monotonic global indexes along dimension y
```","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/4213/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue