DarkEnergyCameraRawFormatter

class lsst.obs.decam.DarkEnergyCameraRawFormatter(*args, **kwargs)

Bases: lsst.obs.base.FitsRawFormatterBase

Attributes Summary

dataId DataId associated with this formatter (DataCoordinate)
extension
fileDescriptor FileDescriptor associated with this formatter (FileDescriptor, read-only)
filterDefinitions
metadata The metadata read from this file.
observationInfo The ObservationInfo extracted from this file’s metadata (ObservationInfo, read-only).
supportedExtensions
supportedWriteParameters
unsupportedParameters
wcsFlipX
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 = <lsst.obs.base.filters.FilterDefinitionCollection object>
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({'.fz', '.fits.fz', '.fit', '.fits', '.fits.gz'})
supportedWriteParameters = frozenset({'recipe'})
unsupportedParameters = {}
wcsFlipX = True
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.