issue_comments: 1338121102

This data as json

html_url issue_url id node_id user created_at updated_at author_association body reactions performed_via_github_app issue
https://github.com/pydata/xarray/issues/7350#issuecomment-1338121102 https://api.github.com/repos/pydata/xarray/issues/7350 1338121102 IC_kwDOAMm_X85PwhuO 1217238 2022-12-05T20:23:46Z 2022-12-05T20:23:46Z MEMBER

IMO, it's not correctly implementing the rule as you phrased it. You said "still present", which isn't the case here since the coordinate wasn't present before.

Another way of describing the current behavior would be that xarray keeps around "every coordinate which could possibly still be valid," which is determined based upon dimension names.

The main challenge is that "Coordinate variables should not have their coordinates changed" doesn't really make sense in Xarray's data model. Only Dataset or DataArray objects have coordinates, which apply to the the entire Dataset/DataArray.

Let me give an example of why we might want to keep scalar coordinates around. Consider a Dataset where lat and lon need to be represented as 2D arrays, along x and y dimensions. If we index out a single lat/lon point, i.e., ds.isel(x=0, y=0) it would have scalar coordinates "x", "y", "lat" and "lon." If we now convert any of these to a DataArray, arguably all the coordinates are still valid.

 
{
    "total_count": 0,
    "+1": 0,
    "-1": 0,
    "laugh": 0,
    "hooray": 0,
    "confused": 0,
    "heart": 0,
    "rocket": 0,
    "eyes": 0
}
   1473329967