Source Catalogs¶

A module that manages catalogs and source finding algorithms (i.e., SExtractor source finding).

Author:	Mihai Cara (for help, contact HST Help Desk)
License:	LICENSE

class subpixal.catalogs.SourceCatalog[source]¶

A class for handling catalog data: storing, filtering, and retrieving sources.

append_filters(fcond)[source]¶: Add one or more conditions for selecting sources from the raw catalog to already set filters. See set_filters() for description of parameter fcond.

catalog¶: Get catalog (after applying masks and selection filters).

catmap¶: Get raw catalog column name mapping.

execute()[source]¶: Compute catalog applying masks and selecting only sources that satisfy all set filters.

filters¶: Get a list of all active selection filters.

is_dirty()[source]¶: Returns the “dirty” status. When a catalog is marked as “dirty”, sources must be (re-)extracted from the raw catalog. In order to update

mark_dirty()[source]¶: Mark the catalog as “dirty”, indicating whether or not sources should be re-extracted from the raw catalog when execute() is run. Masking and filtering criteria will be applied to the raw catalog during this run of execute().

mask¶: Get mask indicating “bad” (True) and “good” (False) sources when mask_type is 'image' or a 2D array of shape (N, 2) containing integer coordinates of “bad” pixels.

mask_type¶: Get mask type: ‘coords’, ‘image’, or None (mask not set).

predefined_catmaps¶: Get names of available (pre-defined) column name mappings.

rawcat¶: Get raw catalog.

rawcat_colnames¶: Get a list of the column names in the raw catalog after catalog column name mapping has been applied.

remove_filter(key, op=None)[source]¶

Remove a specific filter by column name and, optionally, by comparison operator.

Parameters:	key : str Column name to which selection criteria (filter) is applied. If more conditions match a column name vale, all of them will be removed. op : str, optional Specifies the comparison operation used in a filter. This allows narrowing down which filters should be removed.

required_colnames¶: Get a list of the minimum column names that are required to be present in the raw catalog after catalog column name mapping has been applied.

reset_filters()[source]¶: Remove selection filters.

set_default_filters()[source]¶: Set default source selection criteria.

set_filters(fcond)[source]¶

Set conditions for selecting sources from the raw catalog.

Parameters:

fcond : tuple, list of tuples

Each selection condition must be specified as a tuple of the form (colname, comp, value) where:

colname is a column name from the raw catalog after catalog column name mapping has been applied. Use rawcat_colnames to get a list of available column names.
comp is a string representing a comparison operator. The following operators are suported: ['>', '>=', '==', '!=', '<', '<='].
value is a numeric value to be used for comparison of column values.

Multiple selection conditions can be provided as a list of the condition tuples described above.

set_raw_catalog(rawcat, catmap=None, origin=0)[source]¶

Parameters:

rawcat : astropy.table.Table: An Table containing source data.
catmap : dict, str, optional: A dict that provides mapping (a dictionary) between source’s 'x', 'y', 'flux', etc. and the corresponding column names in a Table catalog. Instead of a dictionary, this parameter may be a pre-defined mapping name supported by this class. To get the list of all pre-defined catalog mapping supported by this class, use SourceCatalog’s predefined_catmaps property. When catmap is None, no column name mapping will be applied.
origin: int, float, optional: Coordinates of the sources of SourceCatalog.catalog are zero-based. The origin is used for converting rawcat’s coordinates when raw catalog’s source coordinates are not zero-based.

class subpixal.catalogs.SExCatalog(rawcat=None, max_stellarity=1.0)[source]¶

A catalog class specialized for handling SExtractor output catalogs, such as being able to load raw SExtractor catalogs directly from text files.

Parameters:	rawcat : astropy.table.Table, str An `Table` containing source data or a `SExtractor`-generated text file name. max_stellarity : float, optional Maximum stellarity for selecting sources from the catalog.

set_default_filters()[source]¶

Sets default filters for selecting sources from the raw catalog.

Default selection criteria are: flux > 0 AND fwhm > 0 AND radius > 0 AND prof-rms-a > 0 AND prof-rms-b > 0 AND stellarity <= max_stellarity.

set_raw_catalog(rawcat)[source]¶

Set/replace raw catalog.

Parameters:	rawcat : astropy.table.Table, str An `Table` containing source data or a `SExtractor`-generated text file name.

class subpixal.catalogs.SExImageCatalog(image=None, sexconfig=None, max_stellarity=1.0, sextractor_cmd='sex')[source]¶

A catalog class specialized for finding sources in images using SExtractor and then loading raw SExtractor catalogs directly from output text files.

Parameters:	image : str A `FITS` image file name. sexconfig : str File name of the `SExtractor` configuration file to be used for finding sources in the `image`. max_stellarity : float, optional Maximum stellarity for selecting sources from the catalog. sextractor_cmd : str, optional Command to invoke `SExtractor`.

execute()[source]¶: Compute catalog applying masks and selecting only sources that satisfy all set filters.

image¶: Get image.

segmentation_file¶: Get segmentation file name stored in the SExtractor’s configuration file or None.

sexconfig¶: Get SExtractor configuration file.