Added a new figure to summarize metadata categories, expect it would help readers to visually comprehend metadata categories outlined in the document.
Added new 'mandatory' attribute called 'calibration' under calibration attributes. This mandatory field may help to define whether processed data is calibrated or not. It is possible that uncalibrated (good quality data) can be produced for qualitative studies, in this case a top-level attribute 'calibration' would help users to define the calibration status of their data.
In view of the above change, altered obligations of calibration_date, calibration_acquisition_method, calibration_processing_method, calibration_accuracy_estimate, and calibration_report from 'M' to 'MA'.
Added new 'mandatory' attribute called 'platform_mobility' under platform attributes. This mandatory field may help to define mobility of a platform with controlled vocabulary 'Fixed' or 'Mobile'.
Minor edits to 'Revisions' section to incorporate previously approved changes.
Commits are detailed below.