Consider adding functionality like `odc.geo.xr.replace_coords()`

[alexgleith]

Current options to write data out with a different definition of geobox coordinates include either:

a) using the private method

_write_cog(
      data,
      new_geobox,
      output_file,
)

b) assigning coordinates, which has a fixed coordinate name

# Set up a new Affine and GeoBox
new_affine = Affine(0.01, 0.0, -180.0, 0.0, 0.01, -89.995, 0.0, 0.0, 1.0)
new_geobox = GeoBox(data.odc.geobox.shape, new_affine, data.odc.geobox.crs)

new_coords = xr_coords(new_geobox)

# Rename lat to latitude and lon to longitude and update the coordinates of the xarray
new_data = data.rename({"lat": "latitude", "lon": "longitude"}).assign_coords(
    new_coords
)

So having a functionality that can safely do with without compromise or complexity would be nice.

[Kirill888]

We should try to keep same style as xarray api, they tend to use set_ prefix, used to be assign_, but that seems to be deprecated. So something like set_geo_coords :: GeoBox -> xr.Dataset | xr.DataArray making sure to return a new xarray object wrapping same pixel data.

[alexgleith]

Possibly need to pass in dimension names too. Or to infer them, perhaps it's an implementation detail.

[Kirill888]

currently, these are fixed to y,x or latitude,longitude based on CRS, but xr_coords should make it easy to

1. force to always be y,x
2. use custom names

and the proposed method should just delegate that part to xr_coords (pass-through kwargs). It should also ensure that whatever other, non-spatial dimensions and coords are present on input remain on output also.

Essentially what we want is xx | drop-geo-coords | set-geo-coords [opts]

[robbibt]

Is this issue mostly resolved by the addition of .odc.reload() @Kirill888/@alexgleith? https://odc-geo.readthedocs.io/en/latest/_api/odc.geo.xr.ODCExtensionDa.reload.html

If so, we might want to add a little extra to those docstrings to explain how it could be used in a scenario like this.

[alexgleith]

I don't think so, @robbibt. Sometimes automatic coordinate loading leads to bad numbers due to floating point precision. (i.e., 1.9999999 rather than 2.0).

So explicitly setting the geobox, although it's dangerous, is useful sometimes.

[Kirill888]

So does something like:

xx = xx.assign_coords(odc.geo.xr.xr_coords(actual_geobox_you_want))

do what you need in this case @alexgleith

[Kirill888]

I guess I don't understand why you need to rename and keep old coords on the same dataset. Or is the problem in figuring out what actual_geobox_you_want from geobox_in_the_data_currently.

The problem of "I put one geobox in, but what I'm getting back is slightly different" should have been fixed by recent changes that take more care to re-use original affine matrix where possible instead of recomputing from coordinate data.

[alexgleith]

I guess I don't understand why you need to rename

It was throwing an error before. Looks like it's not required now, which is nice.

[alexgleith]

There seems to be a geobox per variable now, @Kirill888

data.odc.geobox.affine

[0.01, 0.0, -180.0, 0.0, -0.01, 89.995, 0.0, 0.0, 1.0]

list(data.analysed_sst.odc.geobox.affine)

[0.010009765625, 0.0, -179.99501037597656, 0.0, -0.0099945068359375, 89.9949951171875, 0.0, 0.0, 1.0]

[alexgleith]

Reported over here https://github.com/opendatacube/odc-geo/issues/157