Schematron using XPath 2.0 The attribute @unit must be equal to one of the following values 'arcmin', 'arcsec', 'deg', 'hr', 'microrad', 'mrad', 'rad'. The attribute @unit must be equal to one of the following values 'arcmin', 'arcsec', 'deg', 'hr', 'microrad', 'mrad', 'rad'. The attribute survey:Corner_Position/survey:corner_identification must be equal to one of the following values 'Bottom Left', 'Bottom Right', 'Top Left', 'Top Right'. If "Image_Corners" is specified and the product contains an image, a "Display_Settings" must be specified, as well. The attribute survey:Limiting_Magnitudes/survey:reference_object_type must be equal to one of the following values 'Asteroid', 'Comet', 'Galaxy', 'Star'. The rollover_fwhm must have unit = 'arcsec'. The attribute @unit must be equal to one of the following values 'arcmin', 'arcsec', 'deg', 'hr', 'microrad', 'mrad', 'rad'. A top-left corner must be provided A top-right corner must be provided A bottom-left corner must be provided A bottom-right corner must be provided The attribute survey:Survey/survey:calibration_type must be equal to one of the following values 'Bias', 'Dark', 'Flat Field', 'Fringe Correction'. The attribute survey:Survey/survey:observation_purpose must be equal to one of the following values 'Calibration', 'Followup', 'Survey'. The attribute survey:Survey/survey:observation_technique must be equal to one of the following values 'Non-Sidereal Drift Scan', 'Non-Sidereal Stare', 'Sidereal Drift Scan', 'Sidereal Stare', 'Track-And-Stack'. Observations that are not for calibration must specify the image corners. The "Calibration" observation type may only be used with Products with a purpose of "Calibration"