ieeg_epilepsy / ieeg_epilepsy_ecog: Fix CoordinateSystem

[ftadel]

related #215

[sappelhoff]

I seems like I made the impression that I was very strict and determined to have all keywords relating to the table from appendix VIII removed --> sorry for that.

I think this does not need to be fixed - instead I will open 2 PRs: one to BIDS-specification (see the plan discussion: bids-standard/bids-specification#661 (comment)) and one to the bids-validator that will make coordinate system definitions like the one here valid.

Once all of that is thoroughly discussed and implemented, we can revisit this dataset.

[sappelhoff]

From your suite of PRs this is the only one that I can't merge right now. I am hopeful that with bids-standard/bids-specification#700 the change

- "iEEGCoordinateSystem": "MNI152",
+ "iEEGCoordinateSystem": "Other",

won't be necessary and we can keep MNI152, as it's also listed in the table here: https://bids-specification.readthedocs.io/en/stable/99-appendices/08-coordinate-systems.html#standard-template-identifiers

one change that'd have to be made though (if my PR goes through as it is currently) concerns the sub-ecog01_ses-postimp_space-other_coordsystem.json file, where the electrode coords are to be interpreted with regards to sub-ecog01/ses-postimp/anat/sub-ecog01_ses-postimp_T1w.nii.gz

there, instead of "Other" the keyword "Image" would be used if it goes according to the current state of the PR.

[sappelhoff]

I am going ahead and will incorporate parts of your PR into #226.

Thanks!