FitsRawFormatterBase

class lsst.obs.base.FitsRawFormatterBase(*args, **kwargs)

Bases: lsst.obs.base.formatters.fitsExposure.FitsImageFormatterBase

Abstract base class for reading and writing raw data to and from FITS files.

Attributes Summary

checked_parameters The parameters passed by the butler user, after checking them against the storage class and transforming None into an empty dict (dict).
dataId Return Data ID associated with this formatter (DataCoordinate).
extension
fileDescriptor File descriptor associated with this formatter (FileDescriptor).
filterDefinitions FilterDefinitions, defining the filters for this instrument.
metadata The metadata read from this file.
observationInfo The ObservationInfo extracted from this file’s metadata (ObservationInfo, read-only).
supportedExtensions
supportedWriteParameters
translatorClass MetadataTranslator to translate metadata header to ObservationInfo.
unsupportedParameters
wcsFlipX Control whether the WCS is flipped in the X-direction (bool)
writeParameters Parameters to use when writing out datasets.
writeRecipes Detailed write Recipes indexed by recipe name.

Methods Summary

attachComponentsFromMetadata(exposure) Attach all lsst.afw.image.Exposure components derived from metadata (including the stripped metadata itself).
can_read_bytes() Indicate if this formatter can format from bytes.
fromBytes(serializedDataset, component) Read serialized data into a Dataset or its component.
fromMetadata(metadata[, obsInfo, …]) Construct a possibly-limited formatter from known metadata.
getDetector(id) Return the detector that acquired this raw exposure.
isOnSky() Boolean to determine if the exposure is thought to be on the sky.
makeFilter() Construct a Filter from metadata.
makeFilterLabel() Construct a FilterLabel from metadata.
makeRawSkyWcsFromBoresight(boresight, …) Class method to make a raw sky WCS from boresight and detector.
makeUpdatedLocation(location) Return a new Location updated with this formatter’s extension.
makeVisitInfo() Construct a VisitInfo from metadata.
makeWcs(visitInfo, detector) Create a SkyWcs from information about the exposure.
name() Return the fully qualified name of the formatter.
predictPath() Return the path that would be returned by write.
read([component]) Read a Dataset.
readComponent(component) Read a component dataset.
readFull() Read the full dataset (while still accounting for parameters).
readImage() Read just the image component of the Exposure.
readMetadata() Read all header metadata directly into a PropertyList.
segregateParameters(parameters, Any]] = None) Segregate the supplied parameters.
stripMetadata() Remove metadata entries that are parsed into components.
toBytes(inMemoryDataset) Serialize the Dataset to bytes based on formatter.
validateExtension(location) Check the extension of the provided location for compatibility.
validateWriteRecipes(recipes, Any]]) Validate supplied recipes for this formatter.
write(inMemoryDataset) Write a Python object to a file.

Attributes Documentation

checked_parameters

The parameters passed by the butler user, after checking them against the storage class and transforming None into an empty dict (dict).

This is computed on first use and then cached. It should never be accessed when writing. Subclasses that need additional checking should delegate to super and then check the result before returning it.

dataId

Return Data ID associated with this formatter (DataCoordinate).

extension = '.fits'
fileDescriptor

File descriptor associated with this formatter (FileDescriptor).

Read-only property.

filterDefinitions

FilterDefinitions, defining the filters for this instrument.

metadata

The metadata read from this file. It will be stripped as components are extracted from it (lsst.daf.base.PropertyList).

observationInfo

The ObservationInfo extracted from this file’s metadata (ObservationInfo, read-only).

supportedExtensions = frozenset({'.fit', '.fz', '.fits', '.fits.fz', '.fits.gz'})
supportedWriteParameters = None
translatorClass

MetadataTranslator to translate metadata header to ObservationInfo.

unsupportedParameters = {}
wcsFlipX = False

Control whether the WCS is flipped in the X-direction (bool)

writeParameters

Parameters to use when writing out datasets.

writeRecipes

Detailed write Recipes indexed by recipe name.

Methods Documentation

attachComponentsFromMetadata(exposure)

Attach all lsst.afw.image.Exposure components derived from metadata (including the stripped metadata itself).

Parameters:
exposure : lsst.afw.image.Exposure

Exposure to attach components to (modified in place). Must already have a detector attached.

classmethod can_read_bytes() → bool

Indicate if this formatter can format from bytes.

Returns:
can : bool

True if the fromBytes method is implemented.

fromBytes(serializedDataset: bytes, component: Optional[str] = None) → object

Read serialized data into a Dataset or its component.

Parameters:
serializedDataset : bytes

Bytes object to unserialize.

component : str, optional

Component to read from the Dataset. Only used if the StorageClass for reading differed from the StorageClass used to write the file.

Returns:
inMemoryDataset : object

The requested data as a Python object. The type of object is controlled by the specific formatter.

classmethod fromMetadata(metadata, obsInfo=None, storageClass=None, location=None)

Construct a possibly-limited formatter from known metadata.

Parameters:
metadata : lsst.daf.base.PropertyList

Raw header metadata, with any fixes (see astro_metadata_translator.fix_header) applied but nothing stripped.

obsInfo : astro_metadata_translator.ObservationInfo, optional

Structured information already extracted from metadata. If not provided, will be read from metadata on first use.

storageClass : lsst.daf.butler.StorageClass, optional

StorageClass for this file. If not provided, the formatter will only support makeWcs, makeVisitInfo, makeFilter, and other operations that operate purely on metadata and not the actual file.

location : lsst.daf.butler.Location, optional.

Location of the file. If not provided, the formatter will only support makeWcs, makeVisitInfo, makeFilter, and other operations that operate purely on metadata and not the actual file.

Returns:
formatter : FitsRawFormatterBase

An instance of cls.

getDetector(id)

Return the detector that acquired this raw exposure.

Parameters:
id : int

The identifying number of the detector to get.

Returns:
detector : Detector

The detector associated with that id.

isOnSky()

Boolean to determine if the exposure is thought to be on the sky.

Returns:
onSky : bool

Returns True if the observation looks like it was taken on the sky. Returns False if this observation looks like a calibration observation.

Notes

If there is tracking RA/Dec information associated with the observation it is assumed that the observation is on sky. Currently the observation type is not checked.

makeFilter()

Construct a Filter from metadata.

Returns:
filter : Filter

Object that identifies the filter for this image.

Raises:
NotFoundError

Raised if the physical filter was not registered via defineFilter.

Deprecated since version v22: Replaced with makeFilterLabel. Will be removed after v22.

makeFilterLabel()

Construct a FilterLabel from metadata.

Returns:
filter : FilterLabel

Object that identifies the filter for this image.

classmethod makeRawSkyWcsFromBoresight(boresight, orientation, detector)

Class method to make a raw sky WCS from boresight and detector.

Parameters:
boresight : lsst.geom.SpherePoint

The ICRS boresight RA/Dec

orientation : lsst.geom.Angle

The rotation angle of the focal plane on the sky.

detector : lsst.afw.cameraGeom.Detector

Where to get the camera geomtry from.

Returns:
skyWcs : SkyWcs

Reversible mapping from pixel coordinates to sky coordinates.

makeUpdatedLocation(location: lsst.daf.butler.core.location.Location) → lsst.daf.butler.core.location.Location

Return a new Location updated with this formatter’s extension.

Parameters:
location : Location

The location to update.

Returns:
updated : Location

A new Location with a new file extension applied.

Raises:
NotImplementedError

Raised if there is no extension attribute associated with this formatter.

Notes

This method is available to all Formatters but might not be implemented by all formatters. It requires that a formatter set an extension attribute containing the file extension used when writing files. If extension is None the supplied file will not be updated. Not all formatters write files so this is not defined in the base class.

makeVisitInfo()

Construct a VisitInfo from metadata.

Returns:
visitInfo : VisitInfo

Structured metadata about the observation.

makeWcs(visitInfo, detector)

Create a SkyWcs from information about the exposure.

If VisitInfo is not None, use it and the detector to create a SkyWcs, otherwise return the metadata-based SkyWcs (always created, so that the relevant metadata keywords are stripped).

Parameters:
visitInfo : VisitInfo

The information about the telescope boresight and camera orientation angle for this exposure.

detector : Detector

The detector used to acquire this exposure.

Returns:
skyWcs : SkyWcs

Reversible mapping from pixel coordinates to sky coordinates.

Raises:
InitialSkyWcsError

Raised if there is an error generating the SkyWcs, chained from the lower-level exception if available.

classmethod name() → str

Return the fully qualified name of the formatter.

Returns:
name : str

Fully-qualified name of formatter class.

predictPath() → str

Return the path that would be returned by write.

Does not write any data file.

Uses the FileDescriptor associated with the instance.

Returns:
path : str

Path within datastore that would be associated with the location stored in this Formatter.

read(component=None)

Read a Dataset.

Parameters:
component : str, optional

Component to read from the file. Only used if the StorageClass for reading differed from the StorageClass used to write the file.

Returns:
inMemoryDataset : object

The requested Dataset.

readComponent(component)

Read a component dataset.

Parameters:
component : str, optional

Component to read from the file.

Returns:
obj : component-dependent

In-memory component object.

Raises:
KeyError

Raised if the requested component cannot be handled.

readFull()

Read the full dataset (while still accounting for parameters).

Returns:
obj : component-dependent

In-memory component object.

readImage()

Read just the image component of the Exposure.

Returns:
image : Image

In-memory image component.

readMetadata()

Read all header metadata directly into a PropertyList.

Returns:
metadata : PropertyList

Header metadata.

segregateParameters(parameters: Optional[Dict[str, Any]] = None) → Tuple[Dict[KT, VT], Dict[KT, VT]]

Segregate the supplied parameters.

This splits the parameters into those understood by the formatter and those not understood by the formatter.

Any unsupported parameters are assumed to be usable by associated assemblers.

Parameters:
parameters : dict, optional

Parameters with values that have been supplied by the caller and which might be relevant for the formatter. If None parameters will be read from the registered FileDescriptor.

Returns:
supported : dict

Those parameters supported by this formatter.

unsupported : dict

Those parameters not supported by this formatter.

stripMetadata()

Remove metadata entries that are parsed into components.

toBytes(inMemoryDataset: Any) → bytes

Serialize the Dataset to bytes based on formatter.

Parameters:
inMemoryDataset : object

The Python object to serialize.

Returns:
serializedDataset : bytes

Bytes representing the serialized dataset.

classmethod validateExtension(location: lsst.daf.butler.core.location.Location) → None

Check the extension of the provided location for compatibility.

Parameters:
location : Location

Location from which to extract a file extension.

Raises:
NotImplementedError

Raised if file extensions are a concept not understood by this formatter.

ValueError

Raised if the formatter does not understand this extension.

Notes

This method is available to all Formatters but might not be implemented by all formatters. It requires that a formatter set an extension attribute containing the file extension used when writing files. If extension is None only the set of supported extensions will be examined.

classmethod validateWriteRecipes(recipes: Optional[Mapping[str, Any]]) → Optional[Mapping[str, Any]]

Validate supplied recipes for this formatter.

The recipes are supplemented with default values where appropriate.

Parameters:
recipes : dict

Recipes to validate.

Returns:
validated : dict

Validated recipes.

Raises:
RuntimeError

Raised if validation fails. The default implementation raises if any recipes are given.

write(inMemoryDataset)

Write a Python object to a file.

Parameters:
inMemoryDataset : object

The Python object to store.

Returns:
path : str

The URI where the primary file is stored.