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BEP016: diffusion derivatives
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Orientation specification required only for directionally-encoded quantities #79

Closed arokem closed 4 months ago

arokem commented 1 year ago

Currently, orientation specification details (e.g., Directions) are designated as REQUIRED metadata, but they should not be required for mdp that are directionally invariant (e.g., FA). We should clarify that.

SphericalHarmonicBasis and SphericalHarmonicDegree are in addition also only relevant for representations that use spherical harmonics, so they should only be REQUIRED for those cases. Again, needs clarification.

Lestropie commented 1 year ago

The intention was for the prior column, "Relevant data representations", to impose restrictions at a higher level. Ie. Since SphericalHarmonicBasis is only "relevant" for "Spherical harmonics", the "REQUIRED" designation applies only when the data representation is "spherical harmonics". However you're right in that this hierarchical state of requirements of metadata is unclear.

I would add also that eg. if the data representation is something other than "Spherical harmonics", then a metadata field like SphericalHarmonicBasis MUST NOT be specified.

So both cases require qualification before the table is presented.