lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader Class Reference

Public Member Functions
	__init__ (self, dataIds, refCats, name=None, log=None, config=None)
	applyProperMotions (self, catalog, epoch)
	getMetadataBox (self, bbox, wcs, filterName, epoch=None, bboxToSpherePadding=100)
	loadPixelBox (self, bbox, wcs, filterName, epoch=None, bboxToSpherePadding=100)
	loadRegion (self, region, filterName, filtFunc=None, epoch=None)
	loadSkyCircle (self, ctrCoord, radius, filterName, epoch=None)

Static Public Member Functions
	getMetadataCircle (coord, radius, filterName, epoch=None)

Public Attributes
	config
	dataIds
	refCats
	name
	log

Static Public Attributes
	ConfigClass = LoadReferenceObjectsConfig

Static Protected Member Functions
	_remapReferenceCatalogSchema (refCat, *anyFilterMapsToThis=None, filterMap=None, centroids=False)
	_addFluxAliases (schema, anyFilterMapsToThis=None, filterMap=None)
	_makeBoxRegion (BBox, wcs, BBoxPadding)
	_calculateCircle (bbox, wcs, pixelMargin)

Detailed Description

This class facilitates loading reference catalogs.

The QuantumGraph generation will create a list of datasets that may
possibly overlap a given region. These datasets are then used to construct
an instance of this class. The class instance should then be passed into
a task which needs reference catalogs. These tasks should then determine
the exact region of the sky reference catalogs will be loaded for, and
call a corresponding method to load the reference objects.

Parameters
----------
dataIds : iterable of `lsst.daf.butler.DataCoordinate`
    An iterable object of data IDs that point to reference catalogs.
refCats : iterable of `lsst.daf.butler.DeferredDatasetHandle`
    Handles to load refCats on demand.
name : `str`, optional
    The name of the refcat that this object will load. This name is used
    for applying colorterms, for example.
config : `LoadReferenceObjectsConfig`
    Configuration of this reference loader.
log : `lsst.log.Log`, `logging.Logger` or `None`, optional
    Logger object used to write out messages. If `None` a default
    logger will be used.

Definition at line 159 of file loadReferenceObjects.py.

Constructor & Destructor Documentation

__init__()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.__init__	(		self,
			dataIds,
			refCats,
			name = None,
			log = None,
			config = None )

Definition at line 186 of file loadReferenceObjects.py.

    def __init__(self, dataIds, refCats, name=None, log=None, config=None):
        if config is None:
            config = self.ConfigClass()
        self.config = config
        self.dataIds = dataIds
        self.refCats = refCats
        self.name = name
        self.log = log or logging.getLogger(__name__).getChild("ReferenceObjectLoader")
 

Member Function Documentation

_addFluxAliases()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader._addFluxAliases ( schema, anyFilterMapsToThis = None, filterMap = None )

staticprotected

Add aliases for camera filter fluxes to the schema.

For each camFilter: refFilter in filterMap, adds these aliases:
    <camFilter>_camFlux:      <refFilter>_flux
    <camFilter>_camFluxErr: <refFilter>_fluxErr, if the latter exists
or sets `anyFilterMapsToThis` in the schema.

Parameters
----------
schema : `lsst.afw.table.Schema`
    Schema for reference catalog.
anyFilterMapsToThis : `str`, optional
    Always use this reference catalog filter.
    Mutually exclusive with `filterMap`.
filterMap : `dict` [`str`,`str`], optional
    Mapping of camera filter name: reference catalog filter name.
    Mutually exclusive with `anyFilterMapsToThis`.

Raises
------
RuntimeError
    Raised if any required reference flux field is missing from the
    schema.

Definition at line 301 of file loadReferenceObjects.py.

    def _addFluxAliases(schema, anyFilterMapsToThis=None, filterMap=None):
        """Add aliases for camera filter fluxes to the schema.
 
        For each camFilter: refFilter in filterMap, adds these aliases:
            <camFilter>_camFlux:      <refFilter>_flux
            <camFilter>_camFluxErr: <refFilter>_fluxErr, if the latter exists
        or sets `anyFilterMapsToThis` in the schema.
 
        Parameters
        ----------
        schema : `lsst.afw.table.Schema`
            Schema for reference catalog.
        anyFilterMapsToThis : `str`, optional
            Always use this reference catalog filter.
            Mutually exclusive with `filterMap`.
        filterMap : `dict` [`str`,`str`], optional
            Mapping of camera filter name: reference catalog filter name.
            Mutually exclusive with `anyFilterMapsToThis`.
 
        Raises
        ------
        RuntimeError
            Raised if any required reference flux field is missing from the
            schema.
        """
        # Fail on any truthy value for either of these.
        if anyFilterMapsToThis and filterMap:
            raise ValueError("anyFilterMapsToThis and filterMap are mutually exclusive!")
 
        aliasMap = schema.getAliasMap()
 
        if anyFilterMapsToThis is not None:
            refFluxName = anyFilterMapsToThis + "_flux"
            if refFluxName not in schema:
                msg = f"Unknown reference filter for anyFilterMapsToThis='{refFluxName}'"
                raise RuntimeError(msg)
            aliasMap.set("anyFilterMapsToThis", refFluxName)
            return  # this is mutually exclusive with filterMap
 
        def addAliasesForOneFilter(filterName, refFilterName):
            """Add aliases for a single filter
 
            Parameters
            ----------
            filterName : `str` (optional)
                Camera filter name. The resulting alias name is
                <filterName>_camFlux
            refFilterName : `str`
                Reference catalog filter name; the field
                <refFilterName>_flux must exist.
            """
            camFluxName = filterName + "_camFlux"
            refFluxName = refFilterName + "_flux"
            if refFluxName not in schema:
                raise RuntimeError("Unknown reference filter %s" % (refFluxName,))
            aliasMap.set(camFluxName, refFluxName)
            refFluxErrName = refFluxName + "Err"
            if refFluxErrName in schema:
                camFluxErrName = camFluxName + "Err"
                aliasMap.set(camFluxErrName, refFluxErrName)
 
        if filterMap is not None:
            for filterName, refFilterName in filterMap.items():
                addAliasesForOneFilter(filterName, refFilterName)
 

_calculateCircle()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader._calculateCircle ( bbox, wcs, pixelMargin )

staticprotected

Compute on-sky center and radius of search region.

Parameters
----------
bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
    Pixel bounding box.
wcs : `lsst.afw.geom.SkyWcs`
    WCS; used to convert pixel positions to sky coordinates.
pixelMargin : `int`
    Padding to add to 4 all edges of the bounding box (pixels).

Returns
-------
results : `lsst.pipe.base.Struct`
    A Struct containing:

    - coord : `lsst.geom.SpherePoint`
        ICRS center of the search region.
    - radius : `lsst.geom.Angle`
        Radius of the search region.
    - bbox : `lsst.geom.Box2D`
        Bounding box used to compute the circle.

Definition at line 404 of file loadReferenceObjects.py.

    def _calculateCircle(bbox, wcs, pixelMargin):
        """Compute on-sky center and radius of search region.
 
        Parameters
        ----------
        bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
            Pixel bounding box.
        wcs : `lsst.afw.geom.SkyWcs`
            WCS; used to convert pixel positions to sky coordinates.
        pixelMargin : `int`
            Padding to add to 4 all edges of the bounding box (pixels).
 
        Returns
        -------
        results : `lsst.pipe.base.Struct`
            A Struct containing:
 
            - coord : `lsst.geom.SpherePoint`
                ICRS center of the search region.
            - radius : `lsst.geom.Angle`
                Radius of the search region.
            - bbox : `lsst.geom.Box2D`
                Bounding box used to compute the circle.
        """
        bbox = geom.Box2D(bbox)  # we modify the box, so use a copy
        bbox.grow(pixelMargin)
        coord = wcs.pixelToSky(bbox.getCenter())
        radius = max(coord.separation(wcs.pixelToSky(pp)) for pp in bbox.getCorners())
        return pipeBase.Struct(coord=coord, radius=radius, bbox=bbox)
 

_makeBoxRegion()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader._makeBoxRegion ( BBox, wcs, BBoxPadding )

staticprotected

Definition at line 367 of file loadReferenceObjects.py.

    def _makeBoxRegion(BBox, wcs, BBoxPadding):
        outerLocalBBox = geom.Box2D(BBox)
        innerLocalBBox = geom.Box2D(BBox)
 
        # Grow the bounding box to allow for effects not fully captured by the
        # wcs provided (which represents the current best-guess wcs solution
        # associated with the dataset for which the calibration is to be
        # computed using the loaded and trimmed reference catalog being defined
        # here).  These effects could include pointing errors and/or an
        # insufficient optical distorition model for the instrument.  The idea
        # is to ensure the spherical geometric region created contains the
        # entire region covered by the bbox.
        # Also create an inner region that is sure to be inside the bbox.
        outerLocalBBox.grow(BBoxPadding)
        innerLocalBBox.grow(-1*BBoxPadding)
 
        # Handle the case where the inner bounding box shrank to a zero sized
        # region (which will be the case if the shrunken size of either
        # dimension is less than or equal to zero).  In this case, the inner
        # bounding box is set to the original input bounding box.  This is
        # probably not the best way to handle an empty inner bounding box, but
        # it is what the calling code currently expects.
        if innerLocalBBox.getDimensions() == geom.Extent2D(0, 0):
            innerLocalBBox = geom.Box2D(BBox)
 
        # Convert the corners of the bounding boxes to sky coordinates.
        innerBoxCorners = innerLocalBBox.getCorners()
        innerSphCorners = [wcs.pixelToSky(corner).getVector() for corner in innerBoxCorners]
        innerSkyRegion = sphgeom.ConvexPolygon(innerSphCorners)
 
        outerBoxCorners = outerLocalBBox.getCorners()
        outerSphCorners = [wcs.pixelToSky(corner).getVector() for corner in outerBoxCorners]
        outerSkyRegion = sphgeom.ConvexPolygon(outerSphCorners)
 
        return innerSkyRegion, outerSkyRegion, innerSphCorners, outerSphCorners
 

_remapReferenceCatalogSchema()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader._remapReferenceCatalogSchema ( refCat, * anyFilterMapsToThis = None, filterMap = None, centroids = False )

staticprotected

This function takes in a reference catalog and returns a new catalog
with additional columns defined from the remaining function arguments.

Parameters
----------
refCat : `lsst.afw.table.SimpleCatalog`
    Reference catalog to map to new catalog
anyFilterMapsToThis : `str`, optional
    Always use this reference catalog filter.
    Mutually exclusive with `filterMap`
filterMap : `dict` [`str`,`str`], optional
    Mapping of camera filter name: reference catalog filter name.
centroids : `bool`, optional
    Add centroid fields to the loaded Schema. ``loadPixelBox`` expects
    these fields to exist.

Returns
-------
expandedCat : `lsst.afw.table.SimpleCatalog`
    Deep copy of input reference catalog with additional columns added

Definition at line 254 of file loadReferenceObjects.py.

                                     filterMap=None, centroids=False):
        """This function takes in a reference catalog and returns a new catalog
        with additional columns defined from the remaining function arguments.
 
        Parameters
        ----------
        refCat : `lsst.afw.table.SimpleCatalog`
            Reference catalog to map to new catalog
        anyFilterMapsToThis : `str`, optional
            Always use this reference catalog filter.
            Mutually exclusive with `filterMap`
        filterMap : `dict` [`str`,`str`], optional
            Mapping of camera filter name: reference catalog filter name.
        centroids : `bool`, optional
            Add centroid fields to the loaded Schema. ``loadPixelBox`` expects
            these fields to exist.
 
        Returns
        -------
        expandedCat : `lsst.afw.table.SimpleCatalog`
            Deep copy of input reference catalog with additional columns added
        """
        if anyFilterMapsToThis or filterMap:
            ReferenceObjectLoader._addFluxAliases(refCat.schema, anyFilterMapsToThis, filterMap)
 
        mapper = afwTable.SchemaMapper(refCat.schema, True)
        mapper.addMinimalSchema(refCat.schema, True)
        mapper.editOutputSchema().disconnectAliases()
 
        if centroids:
            # Add and initialize centroid and hasCentroid fields (these are
            # added after loading to avoid wasting space in the saved catalogs).
            # The new fields are automatically initialized to (nan, nan) and
            # False so no need to set them explicitly.
            mapper.editOutputSchema().addField("centroid_x", type=float, doReplace=True)
            mapper.editOutputSchema().addField("centroid_y", type=float, doReplace=True)
            mapper.editOutputSchema().addField("hasCentroid", type="Flag", doReplace=True)
            mapper.editOutputSchema().getAliasMap().set("slot_Centroid", "centroid")
 
        expandedCat = afwTable.SimpleCatalog(mapper.getOutputSchema())
        expandedCat.setMetadata(refCat.getMetadata())
        expandedCat.extend(refCat, mapper=mapper)
 
        return expandedCat
 

applyProperMotions()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.applyProperMotions	(		self,
			catalog,
			epoch )

Apply proper motion correction to a reference catalog.

Adjust position and position error in the ``catalog``
for proper motion to the specified ``epoch``,
modifying the catalog in place.

Parameters
----------
catalog : `lsst.afw.table.SimpleCatalog`
    Catalog of positions, containing at least these fields:

    - Coordinates, retrieved by the table's coordinate key.
    - ``coord_raErr`` : Error in Right Ascension (rad).
    - ``coord_decErr`` : Error in Declination (rad).
    - ``pm_ra`` : Proper motion in Right Ascension (rad/yr,
        East positive)
    - ``pm_raErr`` : Error in ``pm_ra`` (rad/yr), optional.
    - ``pm_dec`` : Proper motion in Declination (rad/yr,
        North positive)
    - ``pm_decErr`` : Error in ``pm_dec`` (rad/yr), optional.
    - ``epoch`` : Mean epoch of object (an astropy.time.Time)
epoch : `astropy.time.Time`
    Epoch to which to correct proper motion.
    If None, do not apply PM corrections or raise if
    ``config.requireProperMotion`` is True.

Raises
------
RuntimeError
    Raised if ``config.requireProperMotion`` is set but we cannot
    apply the proper motion correction for some reason.

Definition at line 195 of file loadReferenceObjects.py.

    def applyProperMotions(self, catalog, epoch):
        """Apply proper motion correction to a reference catalog.
 
        Adjust position and position error in the ``catalog``
        for proper motion to the specified ``epoch``,
        modifying the catalog in place.
 
        Parameters
        ----------
        catalog : `lsst.afw.table.SimpleCatalog`
            Catalog of positions, containing at least these fields:
 
            - Coordinates, retrieved by the table's coordinate key.
            - ``coord_raErr`` : Error in Right Ascension (rad).
            - ``coord_decErr`` : Error in Declination (rad).
            - ``pm_ra`` : Proper motion in Right Ascension (rad/yr,
                East positive)
            - ``pm_raErr`` : Error in ``pm_ra`` (rad/yr), optional.
            - ``pm_dec`` : Proper motion in Declination (rad/yr,
                North positive)
            - ``pm_decErr`` : Error in ``pm_dec`` (rad/yr), optional.
            - ``epoch`` : Mean epoch of object (an astropy.time.Time)
        epoch : `astropy.time.Time`
            Epoch to which to correct proper motion.
            If None, do not apply PM corrections or raise if
            ``config.requireProperMotion`` is True.
 
        Raises
        ------
        RuntimeError
            Raised if ``config.requireProperMotion`` is set but we cannot
            apply the proper motion correction for some reason.
        """
        if epoch is None:
            if self.config.requireProperMotion:
                raise RuntimeError("requireProperMotion=True but epoch not provided to loader.")
            else:
                self.log.debug("No epoch provided: not applying proper motion corrections to refcat.")
                return
 
        # Warn/raise for a catalog in an incorrect format, if epoch was specified.
        if ("pm_ra" in catalog.schema
                and not isinstance(catalog.schema["pm_ra"].asKey(), afwTable.KeyAngle)):
            if self.config.requireProperMotion:
                raise RuntimeError("requireProperMotion=True but refcat pm_ra field is not an Angle.")
            else:
                self.log.warning("Reference catalog pm_ra field is not an Angle; cannot apply proper motion.")
                return
 
        if ("epoch" not in catalog.schema or "pm_ra" not in catalog.schema):
            if self.config.requireProperMotion:
                raise RuntimeError("requireProperMotion=True but PM data not available from catalog.")
            else:
                self.log.warning("Proper motion correction not available for this reference catalog.")
            return
 
        applyProperMotionsImpl(self.log, catalog, epoch)
 

getMetadataBox()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.getMetadataBox	(		self,
			bbox,
			wcs,
			filterName,
			epoch = None,
			bboxToSpherePadding = 100 )

Return metadata about the loaded reference catalog, in an
on-detector box.

This metadata is used for reloading the catalog (e.g., for
reconstituting a normalised match list).

Parameters
----------
bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
    Bounding box for the pixels.
wcs : `lsst.afw.geom.SkyWcs`
    The WCS object associated with ``bbox``.
filterName : `str`
    Name of the camera filter.
epoch : `astropy.time.Time` or `None`,  optional
    Epoch that proper motion and parallax were corrected to, or `None`
    if no such corrections were applied.
bboxToSpherePadding : `int`, optional
    Padding in pixels to account for translating a set of corners into
    a spherical (convex) boundary that is certain to encompass the
    enitre area covered by the box.

Returns
-------
md : `lsst.daf.base.PropertyList`
    The metadata detailing the search parameters used for this
    dataset.

Definition at line 472 of file loadReferenceObjects.py.

                       bboxToSpherePadding=100):
        """Return metadata about the loaded reference catalog, in an
        on-detector box.
 
        This metadata is used for reloading the catalog (e.g., for
        reconstituting a normalised match list).
 
        Parameters
        ----------
        bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
            Bounding box for the pixels.
        wcs : `lsst.afw.geom.SkyWcs`
            The WCS object associated with ``bbox``.
        filterName : `str`
            Name of the camera filter.
        epoch : `astropy.time.Time` or `None`,  optional
            Epoch that proper motion and parallax were corrected to, or `None`
            if no such corrections were applied.
        bboxToSpherePadding : `int`, optional
            Padding in pixels to account for translating a set of corners into
            a spherical (convex) boundary that is certain to encompass the
            enitre area covered by the box.
 
        Returns
        -------
        md : `lsst.daf.base.PropertyList`
            The metadata detailing the search parameters used for this
            dataset.
        """
        circle = self._calculateCircle(bbox, wcs, self.config.pixelMargin)
        md = self.getMetadataCircle(circle.coord, circle.radius, filterName, epoch=epoch)
 
        paddedBbox = circle.bbox
        _, _, innerCorners, outerCorners = self._makeBoxRegion(paddedBbox, wcs, bboxToSpherePadding)
        for box, corners in zip(("INNER", "OUTER"), (innerCorners, outerCorners)):
            for (name, corner) in zip(("UPPER_LEFT", "UPPER_RIGHT", "LOWER_LEFT", "LOWER_RIGHT"),
                                      corners):
                md.add(f"{box}_{name}_RA", geom.SpherePoint(corner).getRa().asDegrees(), f"{box}_corner")
                md.add(f"{box}_{name}_DEC", geom.SpherePoint(corner).getDec().asDegrees(), f"{box}_corner")
        return md
 

getMetadataCircle()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.getMetadataCircle ( coord, radius, filterName, epoch = None )

static

Return metadata about the loaded reference catalog, in an on-sky
circle.

This metadata is used for reloading the catalog (e.g. for
reconstituting a normalized match list).

Parameters
----------
coord : `lsst.geom.SpherePoint`
    ICRS center of the search region.
radius : `lsst.geom.Angle`
    Radius of the search region.
filterName : `str`
    Name of the camera filter.
epoch : `astropy.time.Time` or `None`, optional
    Epoch that proper motion and parallax were corrected to, or `None`
    if no such corrections were applied.

Returns
-------
md : `lsst.daf.base.PropertyList`
    Metadata about the catalog.

Definition at line 435 of file loadReferenceObjects.py.

    def getMetadataCircle(coord, radius, filterName, epoch=None):
        """Return metadata about the loaded reference catalog, in an on-sky
        circle.
 
        This metadata is used for reloading the catalog (e.g. for
        reconstituting a normalized match list).
 
        Parameters
        ----------
        coord : `lsst.geom.SpherePoint`
            ICRS center of the search region.
        radius : `lsst.geom.Angle`
            Radius of the search region.
        filterName : `str`
            Name of the camera filter.
        epoch : `astropy.time.Time` or `None`, optional
            Epoch that proper motion and parallax were corrected to, or `None`
            if no such corrections were applied.
 
        Returns
        -------
        md : `lsst.daf.base.PropertyList`
            Metadata about the catalog.
        """
        md = PropertyList()
        md.add('RA', coord.getRa().asDegrees(), 'field center in degrees')
        md.add('DEC', coord.getDec().asDegrees(), 'field center in degrees')
        md.add('RADIUS', radius.asDegrees(), 'field radius in degrees, minimum')
        # Version 1: Initial version
        # Version 2: JEPOCH for TAI Julian Epoch year of PM/parallax correction
        md.add('SMATCHV', 2, 'SourceMatchVector version number')
        md.add('FILTER', filterName, 'camera filter name for photometric data')
        md.add('TIMESYS', "TAI", "time scale of time keywords")
        md.add('JEPOCH', None if epoch is None else epoch.tai.jyear,
               'Julian epoch (TAI Julian Epoch year) for catalog')
        return md
 

loadPixelBox()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.loadPixelBox	(		self,
			bbox,
			wcs,
			filterName,
			epoch = None,
			bboxToSpherePadding = 100 )

Load reference objects that are within a pixel-based rectangular
region.

This algorithm works by creating a spherical box whose corners
correspond to the WCS converted corners of the input bounding box
(possibly padded).  It then defines a filtering function which looks at
the pixel position of the reference objects and accepts only those that
lie within the specified bounding box.

The spherical box region and filtering function are passed to the
generic loadRegion method which loads and filters the reference objects
from the datastore and returns a single catalog containing the filtered
set of reference objects.

Parameters
----------
bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
    Box which bounds a region in pixel space.
wcs : `lsst.afw.geom.SkyWcs`
    Wcs object defining the pixel to sky (and inverse) transform for
    the supplied ``bbox``.
filterName : `str`
    Name of camera filter.
epoch : `astropy.time.Time` or `None`, optional
    Epoch to which to correct proper motion and parallax, or `None`
    to not apply such corrections.
bboxToSpherePadding : `int`, optional
    Padding to account for translating a set of corners into a
    spherical (convex) boundary that is certain to encompase the
    enitre area covered by the box.

Returns
-------
output : `lsst.pipe.base.Struct`
    Results struct with attributes:

    ``refCat``
        Catalog containing reference objects inside the specified
        bounding box (padded by self.config.pixelMargin).
    ``fluxField``
        Name of the field containing the flux associated with
        ``filterName``.

Raises
------
RuntimeError
    Raised if no reference catalogs could be found for the specified
    region.
TypeError
    Raised if the loaded reference catalogs do not have matching
    schemas.

Definition at line 514 of file loadReferenceObjects.py.

                     bboxToSpherePadding=100):
        """Load reference objects that are within a pixel-based rectangular
        region.
 
        This algorithm works by creating a spherical box whose corners
        correspond to the WCS converted corners of the input bounding box
        (possibly padded).  It then defines a filtering function which looks at
        the pixel position of the reference objects and accepts only those that
        lie within the specified bounding box.
 
        The spherical box region and filtering function are passed to the
        generic loadRegion method which loads and filters the reference objects
        from the datastore and returns a single catalog containing the filtered
        set of reference objects.
 
        Parameters
        ----------
        bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
            Box which bounds a region in pixel space.
        wcs : `lsst.afw.geom.SkyWcs`
            Wcs object defining the pixel to sky (and inverse) transform for
            the supplied ``bbox``.
        filterName : `str`
            Name of camera filter.
        epoch : `astropy.time.Time` or `None`, optional
            Epoch to which to correct proper motion and parallax, or `None`
            to not apply such corrections.
        bboxToSpherePadding : `int`, optional
            Padding to account for translating a set of corners into a
            spherical (convex) boundary that is certain to encompase the
            enitre area covered by the box.
 
        Returns
        -------
        output : `lsst.pipe.base.Struct`
            Results struct with attributes:
 
            ``refCat``
                Catalog containing reference objects inside the specified
                bounding box (padded by self.config.pixelMargin).
            ``fluxField``
                Name of the field containing the flux associated with
                ``filterName``.
 
        Raises
        ------
        RuntimeError
            Raised if no reference catalogs could be found for the specified
            region.
        TypeError
            Raised if the loaded reference catalogs do not have matching
            schemas.
        """
        paddedBbox = geom.Box2D(bbox)
        paddedBbox.grow(self.config.pixelMargin)
        innerSkyRegion, outerSkyRegion, _, _ = self._makeBoxRegion(paddedBbox, wcs, bboxToSpherePadding)
 
        def _filterFunction(refCat, region):
            # Perform an initial "pre filter" step based on the refCat coords
            # and the outerSkyRegion created from the self.config.pixelMargin-
            # paddedBbox plus an "extra" padding of bboxToSpherePadding and the
            # raw wcs.  This should ensure a large enough projected area on the
            # sky that accounts for any projection/distortion issues, but small
            # enough to filter out loaded reference objects that lie well
            # beyond the projected detector of interest.  This step is required
            # due to the very local nature of the wcs available for the
            # sky <--> pixel conversions.
            preFiltFunc = _FilterCatalog(outerSkyRegion)
            refCat = preFiltFunc(refCat, region)
 
            # Add columns to the pre-filtered reference catalog relating their
            # coordinates to equivalent pixel positions for the wcs provided
            # and use to populate those columns.
            refCat = self._remapReferenceCatalogSchema(refCat, centroids=True)
            afwTable.updateRefCentroids(wcs, refCat)
            # No need to filter the catalog if it is entirely contained in the
            # region defined by the inner sky region.
            if innerSkyRegion.contains(region):
                return refCat
            # Create a new reference catalog, and populate it only with records
            # that fall inside the padded bbox.
            filteredRefCat = type(refCat)(refCat.table)
            centroidKey = afwTable.Point2DKey(refCat.schema['centroid'])
            for record in refCat:
                pixCoords = record[centroidKey]
                if paddedBbox.contains(geom.Point2D(pixCoords)):
                    filteredRefCat.append(record)
            return filteredRefCat
        return self.loadRegion(outerSkyRegion, filterName, filtFunc=_filterFunction, epoch=epoch)
 

loadRegion()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.loadRegion	(		self,
			region,
			filterName,
			filtFunc = None,
			epoch = None )

Load reference objects within a specified region.

This function loads the DataIds used to construct an instance of this
class which intersect or are contained within the specified region. The
reference catalogs which intersect but are not fully contained within
the input region are further filtered by the specified filter function.
This function returns a single source catalog containing all reference
objects inside the specified region.

Parameters
----------
region : `lsst.sphgeom.Region`
    This can be any type that is derived from `lsst.sphgeom.Region` and
    should define the spatial region for which reference objects are to
    be loaded.
filtFunc : callable or `None`, optional
    This optional parameter should be a callable object that takes a
    reference catalog and its corresponding region as parameters,
    filters the catalog by some criteria and returns the filtered
    reference catalog. If `None`, an internal filter function is used
    which filters according to if a reference object falls within the
    input region.
filterName : `str`
    Name of camera filter.
epoch : `astropy.time.Time` or `None`, optional
    Epoch to which to correct proper motion and parallax, or `None` to
    not apply such corrections.

Returns
-------
output : `lsst.pipe.base.Struct`
    Results struct with attributes:

    ``refCat``
        Catalog containing reference objects which intersect the
        input region, filtered by the specified filter function.
    ``fluxField``
        Name of the field containing the flux associated with
        ``filterName``.

Raises
------
RuntimeError
    Raised if no reference catalogs could be found for the specified
    region.
TypeError
    Raised if the loaded reference catalogs do not have matching
    schemas.

Definition at line 605 of file loadReferenceObjects.py.

    def loadRegion(self, region, filterName, filtFunc=None, epoch=None):
        """Load reference objects within a specified region.
 
        This function loads the DataIds used to construct an instance of this
        class which intersect or are contained within the specified region. The
        reference catalogs which intersect but are not fully contained within
        the input region are further filtered by the specified filter function.
        This function returns a single source catalog containing all reference
        objects inside the specified region.
 
        Parameters
        ----------
        region : `lsst.sphgeom.Region`
            This can be any type that is derived from `lsst.sphgeom.Region` and
            should define the spatial region for which reference objects are to
            be loaded.
        filtFunc : callable or `None`, optional
            This optional parameter should be a callable object that takes a
            reference catalog and its corresponding region as parameters,
            filters the catalog by some criteria and returns the filtered
            reference catalog. If `None`, an internal filter function is used
            which filters according to if a reference object falls within the
            input region.
        filterName : `str`
            Name of camera filter.
        epoch : `astropy.time.Time` or `None`, optional
            Epoch to which to correct proper motion and parallax, or `None` to
            not apply such corrections.
 
        Returns
        -------
        output : `lsst.pipe.base.Struct`
            Results struct with attributes:
 
            ``refCat``
                Catalog containing reference objects which intersect the
                input region, filtered by the specified filter function.
            ``fluxField``
                Name of the field containing the flux associated with
                ``filterName``.
 
        Raises
        ------
        RuntimeError
            Raised if no reference catalogs could be found for the specified
            region.
        TypeError
            Raised if the loaded reference catalogs do not have matching
            schemas.
        """
        regionLat = region.getBoundingBox().getLat()
        regionLon = region.getBoundingBox().getLon()
        self.log.info("Loading reference objects from %s in region bounded by "
                      "[%.8f, %.8f], [%.8f, %.8f] RA Dec",
                      self.name,
                      regionLon.getA().asDegrees(), regionLon.getB().asDegrees(),
                      regionLat.getA().asDegrees(), regionLat.getB().asDegrees())
        if filtFunc is None:
            filtFunc = _FilterCatalog(region)
        # filter out all the regions supplied by the constructor that do not overlap
        overlapList = []
        for dataId, refCat in zip(self.dataIds, self.refCats):
            # SphGeom supports some objects intersecting others, but is not symmetric,
            # try the intersect operation in both directions
            try:
                intersects = dataId.region.intersects(region)
            except TypeError:
                intersects = region.intersects(dataId.region)
 
            if intersects:
                overlapList.append((dataId, refCat))
 
        if len(overlapList) == 0:
            raise RuntimeError("No reference tables could be found for input region")
 
        firstCat = overlapList[0][1].get()
        refCat = filtFunc(firstCat, overlapList[0][0].region)
        trimmedAmount = len(firstCat) - len(refCat)
 
        # Load in the remaining catalogs
        for dataId, inputRefCat in overlapList[1:]:
            tmpCat = inputRefCat.get()
 
            if tmpCat.schema != firstCat.schema:
                raise TypeError("Reference catalogs have mismatching schemas")
 
            filteredCat = filtFunc(tmpCat, dataId.region)
            refCat.extend(filteredCat)
            trimmedAmount += len(tmpCat) - len(filteredCat)
 
        version = getFormatVersionFromRefCat(refCat)
        if version > LATEST_FORMAT_VERSION:
            raise ValueError(f"Unsupported refcat format version: {version} > {LATEST_FORMAT_VERSION}.")
 
        self.log.debug("Trimmed %d refCat objects lying outside padded region, leaving %d",
                       trimmedAmount, len(refCat))
        self.log.info("Loaded %d reference objects", len(refCat))
 
        # Ensure that the loaded reference catalog is continuous in memory
        if not refCat.isContiguous():
            refCat = refCat.copy(deep=True)
 
        self.applyProperMotions(refCat, epoch)
 
        expandedCat = self._remapReferenceCatalogSchema(refCat,
                                                        anyFilterMapsToThis=self.config.anyFilterMapsToThis,
                                                        filterMap=self.config.filterMap)
 
        # Ensure that the returned reference catalog is continuous in memory
        if not expandedCat.isContiguous():
            expandedCat = expandedCat.copy(deep=True)
 
        fluxField = getRefFluxField(expandedCat.schema, filterName)
        return pipeBase.Struct(refCat=expandedCat, fluxField=fluxField)
 

loadSkyCircle()

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.loadSkyCircle	(		self,
			ctrCoord,
			radius,
			filterName,
			epoch = None )

Load reference objects that lie within a circular region on the sky.

This method constructs a circular region from an input center and
angular radius, loads reference catalogs which are contained in or
intersect the circle, and filters reference catalogs which intersect
down to objects which lie within the defined circle.

Parameters
----------
ctrCoord : `lsst.geom.SpherePoint`
    Point defining the center of the circular region.
radius : `lsst.geom.Angle`
    Defines the angular radius of the circular region.
filterName : `str`
    Name of camera filter.
epoch : `astropy.time.Time` or `None`, optional
    Epoch to which to correct proper motion and parallax, or `None` to
    not apply such corrections.

Returns
-------
output : `lsst.pipe.base.Struct`
    Results struct with attributes:

    ``refCat``
        Catalog containing reference objects inside the specified
        search circle.
    ``fluxField``
        Name of the field containing the flux associated with
        ``filterName``.

Definition at line 720 of file loadReferenceObjects.py.

    def loadSkyCircle(self, ctrCoord, radius, filterName, epoch=None):
        """Load reference objects that lie within a circular region on the sky.
 
        This method constructs a circular region from an input center and
        angular radius, loads reference catalogs which are contained in or
        intersect the circle, and filters reference catalogs which intersect
        down to objects which lie within the defined circle.
 
        Parameters
        ----------
        ctrCoord : `lsst.geom.SpherePoint`
            Point defining the center of the circular region.
        radius : `lsst.geom.Angle`
            Defines the angular radius of the circular region.
        filterName : `str`
            Name of camera filter.
        epoch : `astropy.time.Time` or `None`, optional
            Epoch to which to correct proper motion and parallax, or `None` to
            not apply such corrections.
 
        Returns
        -------
        output : `lsst.pipe.base.Struct`
            Results struct with attributes:
 
            ``refCat``
                Catalog containing reference objects inside the specified
                search circle.
            ``fluxField``
                Name of the field containing the flux associated with
                ``filterName``.
        """
        centerVector = ctrCoord.getVector()
        sphRadius = sphgeom.Angle(radius.asRadians())
        circularRegion = sphgeom.Circle(centerVector, sphRadius)
        return self.loadRegion(circularRegion, filterName, epoch=epoch)
 
 

Member Data Documentation

config

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.config

Definition at line 189 of file loadReferenceObjects.py.

ConfigClass

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.ConfigClass = LoadReferenceObjectsConfig

static

Definition at line 184 of file loadReferenceObjects.py.

dataIds

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.dataIds

Definition at line 190 of file loadReferenceObjects.py.

log

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.log

Definition at line 193 of file loadReferenceObjects.py.

name

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.name

Definition at line 192 of file loadReferenceObjects.py.

refCats

lsst.meas.algorithms.loadReferenceObjects.ReferenceObjectLoader.refCats

Definition at line 191 of file loadReferenceObjects.py.

---

The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/meas_algorithms/ge6526c86ff+0d71447b4b/python/lsst/meas/algorithms/loadReferenceObjects.py