class jwst.datamodels.NIRISSGrismModel(init=None, displ=None, dispx=None, dispy=None, invdispl=None, orders=None, fwcpos_ref=None, **kwargs)[source]

Bases: jwst.datamodels.ReferenceFileModel

A model for a reference file of type “specwcs” for NIRISS grisms.

  • displ (Model) – NIRISS Grism wavelength dispersion model

  • dispx (Model) – NIRISS Grism row dispersion model

  • dispy (Model) – NIRISS Grism column dispersion model

  • invdispl (Model) – NIRISS Grism inverse wavelength dispersion model

  • invdispx (Model) – NIRISS Grism inverse row dispersion model

  • invdispy (Model) – NIRISS Grism inverse column dispersion model

  • orders (Model) – NIRISS Grism orders, matched to the array locations of the dispersion models

  • fwcpos_ref (float) – The reference value for the filter wheel position

  • init (str, tuple, HDUList, ndarray, dict, None) –

    • None : Create a default data model with no shape.

    • tuple : Shape of the data array. Initialize with empty data array with shape specified by the.

    • file path: Initialize from the given file (FITS or ASDF)

    • readable file object: Initialize from the given file object

    • HDUList : Initialize from the given HDUList.

    • A numpy array: Used to initialize the data array

    • dict: The object model tree for the data model

  • schema (dict, str (optional)) – Tree of objects representing a JSON schema, or string naming a schema. The schema to use to understand the elements on the model. If not provided, the schema associated with this class will be used.

  • memmap (bool) – Turn memmap of FITS file on or off. (default: False). Ignored for ASDF files.

  • pass_invalid_values (bool or None) – If True, values that do not validate the schema will be added to the metadata. If False, they will be set to None. If None, value will be taken from the environmental PASS_INVALID_VALUES. Otherwise the default value is False.

  • strict_validation (bool or None) – If True, schema validation errors will generate an exception. If False, they will generate a warning. If None, value will be taken from the environmental STRICT_VALIDATION. Otherwise, the default value is False.

  • ignore_missing_extensions (bool) – When False, raise warnings when a file is read that contains metadata about extensions that are not available. Defaults to True.

  • kwargs (dict) – Additional arguments passed to lower level functions.

  • available built-in formats are (The) –

  • ==== ===== ============= (=========) – Format Read Write Auto-identify

  • ==== ===== =============

  • Yes Yes Yes (datamodel) –

  • ==== ===== =============

Attributes Summary



Methods Summary



Write a data model to a FITS file.


Convenience function to be run when files are created.

Attributes Documentation

reftype = 'specwcs'
schema_url = ''

Methods Documentation


Write a data model to a FITS file.

  • init (file path or file object) –

  • kwargs (args,) – Any additional arguments are passed along to


Convenience function to be run when files are created. Checks that required reference file keywords are set.