FitsOpaqueMetadata#

final class lsst.images.fits.FitsOpaqueMetadata(headers=<factory>, precompressed=<factory>)#

Bases: OpaqueArchiveMetadata

Opaque metadata that may be carried around by a serializable type to propagate serialization options and opaque information without that type knowing how it was serialized.

Parameters:

headers (dict[ExtensionKey, Header], default: <factory>)
precompressed (dict[str, PrecompressedImage], default: <factory>)

Methods Summary

`add_cutdown_primary_header`(header)	Add the primary header of a cut-down `lsst.images` FITS file as opaque metadata.
`add_header`(header[, name, ver, key])	Add a header to the opaque metadata if it is not already present, and strip EXTNAME, EXTVER, and DATE if present.
`copy`()	Copy, reference, or discard metadata when its holding object is copied.
`extract_legacy_primary_header`(header)	Update the opaque metadata with the header of the primary HDU of a legacy (`lsst.afw.image`) FITS file, stripping cards we know we don't need and extracting any `LSST IMAGES ...` cards into a dictionary we return.
`get_instrumental_unit`()	Extract the `LSST ISR UNIT` key from the primary header (if it exists) and wrap it with Astropy.
`maybe_use_precompressed`(name)	Look up the given EXTNAME to see if there is a tile compressed image HDU that should be used directly, instead of requantizing.
`subset`(bbox)	Copy, reference, or discard metadata when a subset of its its holding object is extracted.

Methods Documentation

add_cutdown_primary_header(header)#

Add the primary header of a cut-down lsst.images FITS file as opaque metadata.

A cut-down file is one whose JSON-tree, index, and nested-archive HDUs have been dropped, leaving only the primary, image, mask, and variance HDUs (e.g. as written by dax_images_cutout). Only the container-layout cards that would be misleading after re-serialization are stripped; all other cards are retained so they survive the round trip.

Parameters:: header (Header) – Primary header to read. Not modified.
Return type:: None

add_header(header, name=None, ver=None, key=None)#

Add a header to the opaque metadata if it is not already present, and strip EXTNAME, EXTVER, and DATE if present.

Parameters:

header (Header) – Header to add. May be modified in place.
name (str | None, default: None) – EXTNAME (all caps). If not provided, the EXTNAME card must be present in the header. Use "" for the primary header.
ver (int | None, default: None) – EXTVER. If not provided and the EXTVER card is not present, defaults to 1.
key (ExtensionKey | None, default: None) – Combination of EXTNAME and EXTVER; used instead of both name and ver if provided.

Return type:

None

copy()#

Copy, reference, or discard metadata when its holding object is copied.

Return type:: FitsOpaqueMetadata

extract_legacy_primary_header(header)#

Update the opaque metadata with the header of the primary HDU of a legacy (lsst.afw.image) FITS file, stripping cards we know we don’t need and extracting any LSST IMAGES ... cards into a dictionary we return.

Parameters:: header (Header) – Primary HDU header of the legacy FITS file.
Return type:: dict[str, Any]

get_instrumental_unit()#

Extract the LSST ISR UNIT key from the primary header (if it exists) and wrap it with Astropy.

Return type:: UnitBase | None

maybe_use_precompressed(name)#

Look up the given EXTNAME to see if there is a tile compressed image HDU that should be used directly, instead of requantizing.

Parameters:: name (str) – EXTNAME (all caps).
Returns:: An already-compressed HDU, in binary table form, or None if there is no precompressed HDU for this EXTNAME.
Return type:: astropy.io.fits.BinTableHDU | None

subset(bbox)#

Copy, reference, or discard metadata when a subset of its its holding object is extracted.

Parameters:: bbox (Box) – Bounding box of the subset being extracted.
Return type:: FitsOpaqueMetadata