lsst.meas.base gdd7ff8183c+802e40e51a
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Public Member Functions | Public Attributes | Static Public Attributes | List of all members
lsst.meas.base.forcedMeasurement.ForcedMeasurementTask Class Reference
Inheritance diagram for lsst.meas.base.forcedMeasurement.ForcedMeasurementTask:
lsst.meas.base.baseMeasurement.BaseMeasurementTask

Public Member Functions

def __init__ (self, refSchema, algMetadata=None, **kwds)
 
def run (self, measCat, exposure, refCat, refWcs, exposureId=None, beginOrder=None, endOrder=None)
 
def generateMeasCat (self, exposure, refCat, refWcs, idFactory=None)
 
def attachTransformedFootprints (self, sources, refCat, exposure, refWcs)
 
def attachPsfShapeFootprints (self, sources, exposure, scaling=3)
 

Public Attributes

 mapper
 
 schema
 

Static Public Attributes

 ConfigClass = ForcedMeasurementConfig
 

Detailed Description

Measure sources on an image, constrained by a reference catalog.

A subtask for measuring the properties of sources on a single image,
using an existing "reference" catalog to constrain some aspects of the
measurement.

Parameters
----------
refSchema : `lsst.afw.table.Schema`
    Schema of the reference catalog.  Must match the catalog later passed
    to 'ForcedMeasurementTask.generateMeasCat` and/or
    `ForcedMeasurementTask.run`.
algMetadata : `lsst.daf.base.PropertyList` or `None`
    Will be updated in place to to record information about each
    algorithm. An empty `~lsst.daf.base.PropertyList` will be created if
    `None`.
**kwds
    Keyword arguments are passed to the supertask constructor.

Notes
-----
Note that while `SingleFrameMeasurementTask` is passed an initial
`~lsst.afw.table.Schema` that is appended to in order to create the output
`~lsst.afw.table.Schema`, `ForcedMeasurementTask` is initialized with the
`~lsst.afw.table.Schema` of the reference catalog, from which a new
`~lsst.afw.table.Schema` for the output catalog is created.  Fields to be
copied directly from the reference `~lsst.afw.table.Schema` are added
before ``Plugin`` fields are added.

Definition at line 221 of file forcedMeasurement.py.

Constructor & Destructor Documentation

◆ __init__()

def lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.__init__ (   self,
  refSchema,
  algMetadata = None,
**  kwds 
)

Reimplemented from lsst.meas.base.baseMeasurement.BaseMeasurementTask.

Definition at line 254 of file forcedMeasurement.py.

Member Function Documentation

◆ attachPsfShapeFootprints()

def lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.attachPsfShapeFootprints (   self,
  sources,
  exposure,
  scaling = 3 
)
Attach Footprints to blank sources prior to measurement, by
creating elliptical Footprints from the PSF moments.

Parameters
----------
sources : `lsst.afw.table.SourceCatalog`
    Blank catalog (with all rows and columns, but values other than
    ``coord_ra``, ``coord_dec`` unpopulated).
    to which footprints should be attached.
exposure : `lsst.afw.image.Exposure`
    Image object from which peak values and the PSF are obtained.
scaling : `int`, optional
    Scaling factor to apply to the PSF second-moments ellipse in order
    to determine the footprint boundary.

Notes
-----
This is a utility function for use by parent tasks; see
`attachTransformedFootprints` for more information.

Definition at line 463 of file forcedMeasurement.py.

◆ attachTransformedFootprints()

def lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.attachTransformedFootprints (   self,
  sources,
  refCat,
  exposure,
  refWcs 
)
Attach Footprints to blank sources prior to measurement, by
transforming Footprints attached to the reference catalog.

Notes
-----
`~lsst.afw.detection.Footprint`\s for forced photometry must be in the
pixel coordinate system of the image being measured, while the actual
detections may start out in a different coordinate system. This
default implementation transforms the Footprints from the reference
catalog from the WCS to the exposure's WCS, which downgrades
``HeavyFootprint``\s into regular `~lsst.afw.detection.Footprint`\s,
destroying deblend information.

See the documentation for `run` for information about the
relationships between `run`, `generateMeasCat`, and
`attachTransformedFootprints`.

Definition at line 440 of file forcedMeasurement.py.

◆ generateMeasCat()

def lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.generateMeasCat (   self,
  exposure,
  refCat,
  refWcs,
  idFactory = None 
)
Initialize an output catalog from the reference catalog.

Parameters
----------
exposure : `lsst.afw.image.exposureF`
    Image to be measured.
refCat : iterable of `lsst.afw.table.SourceRecord`
    Catalog of reference sources.
refWcs : `lsst.afw.geom.SkyWcs`
    Defines the X,Y coordinate system of ``refCat``.
    This parameter is not currently used.
idFactory : `lsst.afw.table.IdFactory`, optional
    Factory for creating IDs for sources.

Returns
-------
meascat : `lsst.afw.table.SourceCatalog`
    Source catalog ready for measurement.

Notes
-----
This generates a new blank `~lsst.afw.table.SourceRecord` for each
record in ``refCat``. Note that this method does not attach any
`~lsst.afw.detection.Footprint`\ s.  Doing so is up to the caller (who
may call `attachedTransformedFootprints` or define their own method -
see `run` for more information).

Definition at line 400 of file forcedMeasurement.py.

◆ run()

def lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.run (   self,
  measCat,
  exposure,
  refCat,
  refWcs,
  exposureId = None,
  beginOrder = None,
  endOrder = None 
)
Perform forced measurement.

    Parameters
    ----------
    exposure : `lsst.afw.image.exposureF`
        Image to be measured. Must have at least a `lsst.afw.geom.SkyWcs`
        attached.
    measCat : `lsst.afw.table.SourceCatalog`
        Source catalog for measurement results; must be initialized with
        empty records already corresponding to those in ``refCat`` (via
        e.g. `generateMeasCat`).
    refCat : `lsst.afw.table.SourceCatalog`
        A sequence of `lsst.afw.table.SourceRecord` objects that provide
        reference information for the measurement.  These will be passed
        to each plugin in addition to the output
        `~lsst.afw.table.SourceRecord`.
    refWcs : `lsst.afw.geom.SkyWcs`
        Defines the X,Y coordinate system of ``refCat``.
    exposureId : `int`, optional
        Optional unique exposureId used to calculate random number
        generator seed in the NoiseReplacer.
    beginOrder : `int`, optional
        Beginning execution order (inclusive). Algorithms with
        ``executionOrder`` < ``beginOrder`` are not executed. `None` for no limit.
    endOrder : `int`, optional
        Ending execution order (exclusive). Algorithms with
        ``executionOrder`` >= ``endOrder`` are not executed. `None` for no limit.

    Notes
    -----
    Fills the initial empty `~lsst.afw.table.SourceCatalog` with forced
    measurement results.  Two steps must occur before `run` can be called:

    - `generateMeasCat` must be called to create the output ``measCat``
      argument.
    - `~lsst.afw.detection.Footprint`\ s appropriate for the forced sources
      must be attached to the ``measCat`` records. The
      `attachTransformedFootprints` method can be used to do this, but
      this degrades "heavy" (i.e., including pixel values)
      `~lsst.afw.detection.Footprint`\s to regular
      `~lsst.afw.detection.Footprint`\s, leading to non-deblended
      measurement, so most callers should provide
      `~lsst.afw.detection.Footprint`\s some other way. Typically, calling
      code will have access to information that will allow them to provide
      heavy footprints - for instance, `ForcedPhotCoaddTask` uses the
      heavy footprints from deblending run in the same band just before
      non-forced is run measurement in that band.

Definition at line 267 of file forcedMeasurement.py.

Member Data Documentation

◆ ConfigClass

lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.ConfigClass = ForcedMeasurementConfig
static

Definition at line 252 of file forcedMeasurement.py.

◆ mapper

lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.mapper

Definition at line 256 of file forcedMeasurement.py.

◆ schema

lsst.meas.base.forcedMeasurement.ForcedMeasurementTask.schema

Definition at line 264 of file forcedMeasurement.py.


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