FitsRawFormatterBase¶

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

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

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

Attributes Summary

`dataId`	DataId associated with this formatter (`DataCoordinate`)
`extension`
`fileDescriptor`	FileDescriptor associated with this formatter (`FileDescriptor`, read-only)
`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

`can_read_bytes`()	Indicate if this formatter can format from bytes.
`fromBytes`(serializedDataset, component)	Reads 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.
`getImageCompressionSettings`(recipeName)	Retrieve the relevant compression settings for this recipe.
`isOnSky`()	Boolean to determine if the exposure is thought to be on the sky.
`makeFilter`()	Construct a Filter from metadata.
`makeRawSkyWcsFromBoresight`(boresight, …)	Class method to make a raw sky WCS from boresight and detector.
`makeUpdatedLocation`(location)	Return a new `Location` instance updated with this formatter’s extension.
`makeVisitInfo`()	Construct a VisitInfo from metadata.
`makeWcs`(visitInfo, detector)	Create a SkyWcs from information about the exposure.
`name`()	Returns the fully qualified name of the formatter.
`predictPath`()	Return the path that would be returned by write, without actually writing.
`read`([component])	Read data from a file.
`readComponent`(component[, parameters])	Read a component held by the Exposure.
`readFull`([parameters])	Read the full Exposure object.
`readImage`()	Read just the image component of the Exposure.
`readMask`()	Read just the mask component of the Exposure.
`readMetadata`()	Read all header metadata directly into a PropertyList.
`readRawHeaderWcs`([parameters])	Read the SkyWcs stored in the un-modified raw FITS WCS header keys.
`readVariance`()	Read just the variance component of the Exposure.
`segregateParameters`(parameters, Any]] = None)	Segregate the supplied parameters into those understood by the formatter and those not understood by the formatter.
`stripMetadata`()	Remove metadata entries that are parsed into components.
`toBytes`(inMemoryDataset)	Serialize the Dataset to bytes based on formatter.
`validateExtension`(location)	Check that the provided location refers to a file extension that is understood by this formatter.
`validateWriteRecipes`(recipes)	Validate supplied recipes for this formatter.
`write`(inMemoryDataset)	Write a Python object to a file.

Attributes Documentation

dataId¶: DataId associated with this formatter (DataCoordinate)

extension = '.fits'¶

fileDescriptor¶: FileDescriptor associated with this formatter (FileDescriptor, read-only)

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({'.fits', '.fz', '.fits.fz', '.fit', '.fits.gz'})¶

supportedWriteParameters = frozenset({'recipe'})¶

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

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¶

Reads 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`.

getImageCompressionSettings(recipeName)¶

Retrieve the relevant compression settings for this recipe.

Parameters:	recipeName : `str` Label associated with the collection of compression parameters to select.
Returns:	settings : `dict` The selected settings.

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`.

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 instance 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¶

Returns 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, without actually writing.

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 data from a file.

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 data as a Python object. The type of object is controlled by the specific formatter.
Raises:	ValueError Component requested but this file does not seem to be a concrete composite. KeyError Raised when parameters passed with fileDescriptor are not supported.

readComponent(component, parameters=None)¶

Read a component held by the Exposure.

Parameters:	component : `str`, optional Component to read from the file. parameters : `dict`, optional If specified, a dictionary of slicing parameters that overrides those in `fileDescriptor`.
Returns:	obj : component-dependent In-memory component object.
Raises:	KeyError Raised if the requested component cannot be handled.

readFull(parameters=None)¶

Read the full Exposure object.

Parameters:	parameters : `dict`, optional If specified, a dictionary of slicing parameters that overrides those in the `fileDescriptor` attribute.
Returns:	exposure : `Exposure` Complete in-memory exposure.

readImage()¶

Read just the image component of the Exposure.

Returns:	image : `Image` In-memory image component.

readMask()¶

Read just the mask component of the Exposure.

May return None (as the default implementation does) to indicate that there is no mask information to be extracted (at least not trivially) from the raw data. This will prohibit direct reading of just the mask, and set the mask of the full Exposure to zeros.

Returns:	mask : `Mask` In-memory mask component.

readMetadata()¶

Read all header metadata directly into a PropertyList.

Returns:	metadata : `PropertyList` Header metadata.

readRawHeaderWcs(parameters=None)¶: Read the SkyWcs stored in the un-modified raw FITS WCS header keys.

readVariance()¶

Read just the variance component of the Exposure.

May return None (as the default implementation does) to indicate that there is no variance information to be extracted (at least not trivially) from the raw data. This will prohibit direct reading of just the variance, and set the variance of the full Exposure to zeros.

Returns:	image : `Image` In-memory variance component.

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

Segregate the supplied 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 that the provided location refers to a file extension that is understood by this formatter.

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)¶

Validate supplied recipes for this formatter.

The recipes are supplemented with default values where appropriate.

TODO: replace this custom validation code with Cerberus (DM-11846)

Parameters:	recipes : `dict` Recipes to validate. Can be empty dict or `None`.
Returns:	validated : `dict` Validated recipes. Returns what was given if there are no recipes listed.
Raises:	RuntimeError Raised if validation fails.

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.

Navigation

FitsRawFormatterBase¶