RFC-4 comment

RFC-4 comment#

Comment author#

David Stansby

Conflicts of interest (optional)#

None

Summary#

n/a

Significant comments and questions#

Spatial restriction#

RFC-4 defines anatomical orientation metadata.

As currently written, it does not restrict this metadata to be present only on spatial axes.

Because it does not make sense to define an anatomical orientation for non-spatial axes (e.g., channel or time axes), RFC-4 should be updated to specify that anatomical orientation data can only be present on spatial axes.

Default orientation#

RFC 4 currently says the default orientation should be:

  "axes": [
    { "name": "z", "type": "space", "unit": "micrometer", "anatomicalOrientation": "inferior-to-superior" },
    { "name": "y", "type": "space", "unit": "micrometer", "anatomicalOrientation": "posterior-to-anterior" },
    { "name": "x", "type": "space", "unit": "micrometer", "anatomicalOrientation": "left-to-right" }
  ]

It’s not clear how implementations should apply this default however. In particular:

  • Should it only be applied when the axes are called specifically [x, y, z]?

  • Should it be applied when there are other axes?

  • Should it be applied when there are less than three axes? (e.g., just [x, y])

All of this is avoided if there is no default, which I agree with https://github.com/ome/ngff/pull/301 in saying there should not be a default, because there is no way for implementations to know if a image is appropriate to describe using anatomical orientation or not.

Minor comments and questions#

n/a

Recommendation#

n/a

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