Connection to image mask planes

Catalog pixelFlags_* columns are directly derived from image mask planes. Each mask plane bit in the image (BAD, SAT, CR, INTRP, EDGE, etc.) propagates to a corresponding pixel flag in the catalog.

The key mask plane to flag mappings are listed in the table below.

Mask Plane	Catalog Flag	Notes
SAT	pixelFlags_saturated	Saturated pixels.
CR	pixelFlags_cr	Cosmic rays (interpolated in final images).
INTRP	pixelFlags_interpolated	Interpolated pixels (from CRs, defects, saturation).
EDGE	pixelFlags_edge	Image edge (single exposures).
SENSOR_EDGE	pixelFlags_sensor_edge	Detector boundaries (coadds).
BAD	pixelFlags_bad	Known bad pixels (detector defects).
SUSPECT	pixelFlags_suspect	Suspect pixels (near saturation).
NO_DATA	pixelFlags_nodata	No data available.
CLIPPED	pixelFlags_clipped	Outlier rejection during coaddition.
REJECTED	(propagates to CLIPPED)	Input visit excluded during coaddition.
INEXACT_PSF	pixelFlags_inexact_psf	PSF model discontinuous (OR of CLIPPED, REJECTED, SENSOR_EDGE).

Footprint vs center: Flags without Center suffix are set if any pixel in the source footprint has that mask bit. Center flags are set only if a pixel in the central 3x3 box has that bit. For quality filtering, center flags are typically more important since they affect core photometry.

See Visit and Difference Image Mask Planes and Deep and Template Coadd Mask Planes for detailed mask plane descriptions.