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Sure, we would welcome a PRs for this.

On Wed, Jun 5, 2019 at 11:33 PM Jonas notifications@github.com wrote:

Thanks for reminding me, stalte bot, this is still relevant to me.

I think your proposed solution @shoyer https://github.com/shoyer would solve this issue perfectly: expose align's join parameter in the concat function - and please also in open_mfdataset. Would you like a PR for this?

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Thanks for reminding me, stalte bot, this is still relevant to me.

I think your proposed solution @shoyer would solve this issue perfectly: expose align's join parameter in the concat function - and please also in open_mfdataset. Would you like a PR for this?

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I think the right solution here is to relabel the coordinates on each of the datasets that you are concatenating. The alternative behavior here is xarray raising an error in the case of conflicting coordinate labels.

@wqshen, a workaround until a more complete modification to align is available would be to explicitly copy/set the coordinate values on your arrays before using xr.concat(). Alternatively, if it's as simple as stacking along a new tailing axis, you could stack via dask/numpy and then construct a new DataArray passing the coordinates explicitly.

I also have this problem.

I have a list of dataset with all same shaped array at different time, while each have a different coordinate. (Each dataset is centered in the tropical cyclone center, with a same radius width buffer.)

I use xr.concat to concat them along time dimension, this function auto outer-joins coordinates, which makes the final dataset have a larger-shape, but i just want the original dataset shape.

Any solution ?

https://github.com/pydata/xarray/pull/1330 will help, in so far as it adds a join='exact' option that can disable automatic alignment. We would just need to make the join argument used internally in align inside xarray.concat part of the public API for concat.

This only happens in concat.

merge, which happens automatically in many operations, e.g., to decide which coordinates propagate, has different behavior: it automatically drops conflicting coordinate values.

Anyways, I agree: we should try to make this more explicit. We might still keep the "magical" version of concat around, but we should certainly expose the fully explicit version as public API.