get_extract_parameters

jwst.extract_1d.extract.get_extract_parameters(ref_dict, input_model, slitname, sp_order, meta, smoothing_length=None, bkg_fit=None, bkg_order=None, subtract_background=None, use_source_posn=None, position_offset=0.0, model_nod_pair=False, optimize_psf_location=False, extraction_type='box', psf_ref_name='N/A')

Get extraction parameter values.

Parameters:

ref_dictdict or None

For an extract1d reference file in JSON format, ref_dict will be the entire contents of the file. If there is no extract1d reference file, ref_dict will be None.

input_modelJWSTDataModel

This can be either the input science file or one SlitModel out of a list of slits.

slitnamestr

The name of the slit, or “ANY”.

sp_orderint

The spectral order number.

metaObjectNode

The metadata for the actual input model, i.e. not just for the current slit, from input_model.meta.

smoothing_lengthint or None, optional

Width of a boxcar function for smoothing the background regions. If None, the smoothing length will be retrieved from ref_dict, or it will be set to 0 (no background smoothing) if this key is not found in ref_dict. If smoothing_length is not None, that means that the user explicitly specified the value, so that value will be used. This argument is only used if background regions have been specified.

bkg_fitstr or None, optional

The type of fit to apply to background values in each column (or row, if the dispersion is vertical). The default ‘poly’ results in a polynomial fit of order bkg_order. Other options are ‘mean’ and ‘median’. If ‘mean’ or ‘median’ is selected, bkg_order is ignored.

bkg_orderint or None, optional

Polynomial order for fitting to each column (or row, if the dispersion is vertical) of background. If None, the polynomial order will be retrieved from ref_dict, or it will be set to 0 if not found in ref_dict. A value of 0 means that a simple average of the background regions, column by column (or row by row), will be used. If bkg_order is not None, that means that the user explicitly specified the value, so that value will be used. This argument must be positive or zero, and it is only used if background regions have been specified.

subtract_backgroundbool or None, optional

If False, all background parameters will be ignored.

use_source_posnbool or None, optional

If True, the target and background positions specified in ref_dict (or a default target position) will be shifted to account for the actual source location in the data. If None, a default value will be set, based on the exposure type.

position_offsetfloat or None, optional

Pixel offset to apply to the nominal source location. If None, the value specified in ref_dict will be used or it will default to 0.

model_nod_pairbool, optional

If True, and if extraction_type is ‘optimal’, then a negative trace from nod subtraction will be modeled alongside the positive source, if possible.

optimize_psf_locationbool

If True, and if extraction_type is ‘optimal’, then the source location will be optimized, via iterative comparisons of the scene model with the input data.

extraction_typestr, optional

Extraction type (‘box’ or ‘optimal’). Optimal extraction is only available if psf_ref_name is not ‘N/A’. If set to None, optimal extraction will be used if use_source_posn is True.

psf_ref_namestr, optional

The name of the PSF reference file, or “N/A”.

Returns:

extract_paramsdict

Information copied from ref_dict. The items will be selected based on slitname and sp_order. Default values will be assigned if ref_dict is None.