FitsImageFormatter¶

class lsst.obs.base.formatters.fitsExposure.FitsImageFormatter(fileDescriptor: FileDescriptor, dataId: DataCoordinate, writeParameters: dict[str, Any] | None = None, writeRecipes: dict[str, Any] | None = None)¶

Bases: StandardFitsImageFormatterBase

Concrete formatter for reading/writing Image from/to FITS.

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`).
`reader`	The reader object that backs this formatter's read operations.
`supportedExtensions`	Set of all extensions supported by this formatter.
`supportedWriteParameters`	Parameters understood by this formatter that can be used to control how a dataset is serialized.
`unsupportedParameters`	Support all parameters.
`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])	Read serialized data into a Dataset or its component.
`getImageCompressionSettings`(recipeName)	Retrieve the relevant compression settings for this recipe.
`makeUpdatedLocation`(location)	Return a new `Location` updated with this formatter's extension.
`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).
`segregateParameters`([parameters])	Segregate the supplied parameters.
`toBytes`(inMemoryDataset)	Serialize the Dataset to bytes based on formatter.
`validateExtension`(location)	Check the extension of the provided location for compatibility.
`validateWriteRecipes`(recipes)	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.

reader¶

The reader object that backs this formatter’s read operations.

This is computed on first use and then cached. It should never be accessed when writing.

supportedExtensions: ClassVar[Set[str]] = frozenset({'.fit', '.fits', '.fits.fz', '.fits.gz', '.fz'})¶

Set of all extensions supported by this formatter.

Only expected to be populated by Formatters that write files. Any extension assigned to the extension property will be automatically included in the list of supported extensions.

supportedWriteParameters: ClassVar[Set[str] | None] = frozenset({'recipe'})¶: Parameters understood by this formatter that can be used to control how a dataset is serialized. None indicates that no parameters are supported.

unsupportedParameters: ClassVar[Set[str]] = frozenset({})¶: Support all parameters.

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:

canbool: True if the fromBytes method is implemented.

fromBytes(serializedDataset: bytes, component: str | None = None) → object¶

Read serialized data into a Dataset or its component.

Parameters:

serializedDatasetbytes: Bytes object to unserialize.
componentstr, optional: Component to read from the Dataset. Only used if the StorageClass for reading differed from the StorageClass used to write the file.

Returns:

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

getImageCompressionSettings(recipeName)¶

Retrieve the relevant compression settings for this recipe.

Parameters:

recipeNamestr: Label associated with the collection of compression parameters to select.

Returns:

settingsdict: The selected settings.

makeUpdatedLocation(location: Location) → Location¶

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

Parameters:

locationLocation: The location to update.

Returns:

updatedLocation: 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.

classmethod name() → str¶

Return the fully qualified name of the formatter.

Returns:

namestr: 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:

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

read(component=None)¶

Read a Dataset.

Parameters:

componentstr, optional: Component to read from the file. Only used if the StorageClass for reading differed from the StorageClass used to write the file.

Returns:

inMemoryDatasetobject: The requested Dataset.

readComponent(component)¶

Read a component dataset.

Parameters:

componentstr, optional: Component to read from the file.

Returns:

objcomponent-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:

objcomponent-dependent: In-memory component object.

segregateParameters(parameters: dict[str, Any] | None = None) → tuple[dict, dict]¶

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:

parametersdict, 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:

supporteddict: Those parameters supported by this formatter.
unsupporteddict: Those parameters not supported by this formatter.

toBytes(inMemoryDataset: Any) → bytes¶

Serialize the Dataset to bytes based on formatter.

Parameters:

inMemoryDatasetobject: The Python object to serialize.

Returns:

serializedDatasetbytes: Bytes representing the serialized dataset.

classmethod validateExtension(location: Location) → None¶

Check the extension of the provided location for compatibility.

Parameters:

locationLocation: 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:

recipesdict: Recipes to validate. Can be empty dict or None.

Returns:

validateddict: 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:

inMemoryDatasetobject: The Python object to store.

Navigation

FitsImageFormatter¶