lsst.meas.base.plugins.EvaluateLocalWcsPlugin Class Reference

Inheritance diagram for lsst.meas.base.plugins.EvaluateLocalWcsPlugin:

Public Member Functions
	getExecutionOrder (cls)
	__init__ (self, config, name, schema, metadata)
	measure (self, measRecord, exposure, center)
	makeLocalTransformMatrix (self, wcs, center)

Public Attributes
	cdMatrix11Key
	cdMatrix12Key
	cdMatrix21Key
	cdMatrix22Key

Static Public Attributes
	ConfigClass = EvaluateLocalWcsPluginConfig

Protected Attributes
	_scale

Static Protected Attributes
tuple	_scale = (1.0 * lsst.geom.arcseconds).asDegrees()

Detailed Description

Evaluate the local, linear approximation of the Wcs.

The aim is to store the local calib value within the catalog for later
use in the Science Data Model functors.

Definition at line 467 of file plugins.py.

Constructor & Destructor Documentation

__init__()

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.__init__	(		self,
			config,
			name,
			schema,
			metadata )

Reimplemented from lsst.meas.base.wrappers.GenericPlugin.

Definition at line 480 of file plugins.py.

    def __init__(self, config, name, schema, metadata):
        GenericPlugin.__init__(self, config, name, schema, metadata)
        self.cdMatrix11Key = schema.addField(
            f"{name}_CDMatrix_1_1",
            type="D",
            doc="(1, 1) element of the CDMatrix for the linear approximation "
                "of the WCS at the src location. Gives units in radians.")
        self.cdMatrix12Key = schema.addField(
            f"{name}_CDMatrix_1_2",
            type="D",
            doc="(1, 2) element of the CDMatrix for the linear approximation "
                "of the WCS at the src location. Gives units in radians.")
        self.cdMatrix21Key = schema.addField(
            f"{name}_CDMatrix_2_1",
            type="D",
            doc="(2, 1) element of the CDMatrix for the linear approximation "
                "of the WCS at the src location. Gives units in radians.")
        self.cdMatrix22Key = schema.addField(
            f"{name}_CDMatrix_2_2",
            type="D",
            doc="(2, 2) element of the CDMatrix for the linear approximation "
                "of the WCS at the src location. Gives units in radians.")
 

Member Function Documentation

getExecutionOrder()

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.getExecutionOrder

(

cls

)

Get the relative execution order of this plugin.

Must be reimplemented as a class method by concrete derived classes.

Reimplemented from lsst.meas.base.wrappers.GenericPlugin.

Definition at line 477 of file plugins.py.

    def getExecutionOrder(cls):
        return BasePlugin.FLUX_ORDER
 

makeLocalTransformMatrix()

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.makeLocalTransformMatrix	(		self,
			wcs,
			center )

Create a local, linear approximation of the wcs transformation
matrix.

The approximation is created as if the center is at RA=0, DEC=0. All
comparing x,y coordinate are relative to the position of center. Matrix
is initially calculated with units arcseconds and then converted to
radians. This yields higher precision results due to quirks in AST.

Parameters
----------
wcs : `lsst.afw.geom.SkyWcs`
    Wcs to approximate
center : `lsst.geom.Point2D`
    Point at which to evaluate the LocalWcs.

Returns
-------
localMatrix : `numpy.ndarray`
    Matrix representation the local wcs approximation with units
    radians.

Definition at line 511 of file plugins.py.

    def makeLocalTransformMatrix(self, wcs, center):
        """Create a local, linear approximation of the wcs transformation
        matrix.
 
        The approximation is created as if the center is at RA=0, DEC=0. All
        comparing x,y coordinate are relative to the position of center. Matrix
        is initially calculated with units arcseconds and then converted to
        radians. This yields higher precision results due to quirks in AST.
 
        Parameters
        ----------
        wcs : `lsst.afw.geom.SkyWcs`
            Wcs to approximate
        center : `lsst.geom.Point2D`
            Point at which to evaluate the LocalWcs.
 
        Returns
        -------
        localMatrix : `numpy.ndarray`
            Matrix representation the local wcs approximation with units
            radians.
        """
        skyCenter = wcs.pixelToSky(center)
        localGnomonicWcs = lsst.afw.geom.makeSkyWcs(
            center, skyCenter, np.diag((self._scale, self._scale)))
        measurementToLocalGnomonic = wcs.getTransform().then(
            localGnomonicWcs.getTransform().inverted()
        )
        localMatrix = measurementToLocalGnomonic.getJacobian(center)
        return np.radians(localMatrix / 3600)
 
 

measure()

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.measure	(		self,
			measRecord,
			exposure,
			center )

Measure a single source.

It is the responsibility of this method to perform the desired
measurement and record the result in the `measRecord`.

Parameters
----------
measRecord : `lsst.afw.table.SourceRecord`
    Catalog record for the source being measured.
exposure : `lsst.afw.image.Exposure`
    Exposure on which the source is being measured.
center : `lsst.geom.Point2D`
    Pixel coordinates of the object.

Raises
------
MeasurementError
    Raised if the measurement fails for a known/justifiable reason.

Reimplemented from lsst.meas.base.wrappers.GenericPlugin.

Definition at line 503 of file plugins.py.

    def measure(self, measRecord, exposure, center):
        wcs = exposure.getWcs()
        localMatrix = self.makeLocalTransformMatrix(wcs, center)
        measRecord.set(self.cdMatrix11Key, localMatrix[0, 0])
        measRecord.set(self.cdMatrix12Key, localMatrix[0, 1])
        measRecord.set(self.cdMatrix21Key, localMatrix[1, 0])
        measRecord.set(self.cdMatrix22Key, localMatrix[1, 1])
 

Member Data Documentation

_scale [1/2]

tuple lsst.meas.base.plugins.EvaluateLocalWcsPlugin._scale = (1.0 * lsst.geom.arcseconds).asDegrees()

staticprotected

Definition at line 474 of file plugins.py.

_scale [2/2]

lsst.meas.base.plugins.EvaluateLocalWcsPlugin._scale

protected

Definition at line 535 of file plugins.py.

cdMatrix11Key

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.cdMatrix11Key

Definition at line 482 of file plugins.py.

cdMatrix12Key

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.cdMatrix12Key

Definition at line 487 of file plugins.py.

cdMatrix21Key

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.cdMatrix21Key

Definition at line 492 of file plugins.py.

cdMatrix22Key

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.cdMatrix22Key

Definition at line 497 of file plugins.py.

ConfigClass

lsst.meas.base.plugins.EvaluateLocalWcsPlugin.ConfigClass = EvaluateLocalWcsPluginConfig

static

Definition at line 473 of file plugins.py.

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

• /j/snowflake/release/lsstsw/stack/lsst-scipipe-8.0.0/Linux64/meas_base/g212a7c68fe+04a9158687/python/lsst/meas/base/plugins.py