Data conversions#

lsst.cst submodule include operations related to data conversions and format

lsst.cst.conversions.data_id_to_str(data_id)#

Returns a data identifier dictionary to a string

Parameters:

data_id ('dict') – Data identifier dictionary.

Returns:

data_id_str – Data identifier string

Return type:

str

lsst.cst.conversions.get_psf_properties(psf, point)#

Function to obtain PSF properties.

Parameters:

  • psf (lsst.meas.extensions.psfex.PsfexPsf) – PSF object.

  • point (lsst.geom.Point2D) – Coordinate where the PSF is being evaluated.

Returns:

psf_values – PsfProperties object containing psf properties: fhwm, ap_flux, peak and dims.

Return type:

PsfProperties

lsst.cst.conversions.ids_to_str(data_ids)#
Transform a numpy array of ids (long int)

to a comma-separated values string

Parameters:

data_ids (numpy.ndarray) – numpy array with objects id

Returns:

result – String with separated by comma-separated values from the data_ids

Return type:

str

lsst.cst.conversions.shuffle_dataframe(df, random_state=0)#

Return a copy of the dataframe df shuffled, random_state argument may be used to reproduce same shuffling.

Parameters:

  • df (pandas.DataFrame) – dataframe to be shuffled

  • random_state (int) – number to reproduce same randomness

Returns:

result – shuffled dataframe

Return type:

pandas.DataFrame

lsst.cst.conversions.sort_dataframe(df, sort_key, ascending=False, set_index=True)#

Return a sorted copy of the dataframe ‘df’ by index, selecting the desired order (ascending or descending) using the ascending argument, it also exchanges the index of the dataframe for the sort_key if set_index parameter is True (default).

Parameters:

  • df (pandas.DataFrame) – dataframe to be sorted

  • sort_key (str) – column key used to sort the dataframe

  • ascending (bool, optional) – ascending/descending sorting

  • set_index (bool, optional) – set sorted key as the dataframe index

Returns:

result – Copy of the DataFrame sorted using the selected column.

Return type:

pandas.DataFrame

lsst.cst.conversions.tract_patch_from_ra_dec(ra, dec)#

Look for nearest tract-patch information from a coordinate ra-dec.

Parameters:

  • ra (np.float64) – Coordinate ascension.

  • dec (np.float64) – Coordinate declination.

Returns:

value – Tract patch information

Return type:

TractPatchInformation