lsst.meas.astrom gf1cff7945b+9b1555bb6b
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Public Member Functions | Static Public Attributes | Protected Member Functions | Static Protected Attributes | List of all members
lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask Class Reference
Inheritance diagram for lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask:

Public Member Functions

 fitWcs (self, matches, initWcs, bbox=None, refCat=None, sourceCat=None, exposure=None)
 
 initialWcs (self, matches, wcs)
 
 rejectMatches (self, matches, wcs, rejected)
 
 plotFit (self, matches, wcs, rejected)
 

Static Public Attributes

 ConfigClass = FitTanSipWcsConfig
 

Protected Member Functions

 _fitWcs (self, matches, wcs)
 

Static Protected Attributes

str _DefaultName = "fitTanSipWcs"
 

Detailed Description

Fit a TAN-SIP WCS given a list of reference object/source matches.

Definition at line 74 of file fitTanSipWcs.py.

Member Function Documentation

◆ _fitWcs()

lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask._fitWcs ( self,
matches,
wcs )
protected
Fit a Wcs based on the matches and a guess Wcs.

Parameters
----------
matches : `list` of `lsst.afw.table.ReferenceMatch`
    List of sources matched to references.
wcs : `lsst.afw.geom.SkyWcs`
    Current WCS.

Returns
-------
sipObject : `lsst.meas.astrom.sip.CreateWcsWithSip`
    Fitted SIP object.

Definition at line 215 of file fitTanSipWcs.py.

◆ fitWcs()

lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask.fitWcs ( self,
matches,
initWcs,
bbox = None,
refCat = None,
sourceCat = None,
exposure = None )
Fit a TAN-SIP WCS from a list of reference object/source matches

Parameters
----------
matches : `list` of `lsst.afw.table.ReferenceMatch`
    The following fields are read:

    - match.first (reference object) coord
    - match.second (source) centroid

    The following fields are written:

    - match.first (reference object) centroid,
    - match.second (source) centroid
    - match.distance (on sky separation, in radians)

initWcs : `lsst.afw.geom.SkyWcs`
    initial WCS
bbox : `lsst.geom.Box2I`
    the region over which the WCS will be valid (an lsst:afw::geom::Box2I);
    if None or an empty box then computed from matches
refCat : `lsst.afw.table.SimpleCatalog`
    reference object catalog, or None.
    If provided then all centroids are updated with the new WCS,
    otherwise only the centroids for ref objects in matches are updated.
    Required fields are "centroid_x", "centroid_y", "coord_ra", and "coord_dec".
sourceCat : `lsst.afw.table.SourceCatalog`
    source catalog, or None.
    If provided then coords are updated with the new WCS;
    otherwise only the coords for sources in matches are updated.
    Required fields are "slot_Centroid_x", "slot_Centroid_y", and "coord_ra", and "coord_dec".
exposure : `lsst.afw.image.Exposure`
    Ignored; present for consistency with FitSipDistortionTask.

Returns
-------
result : `lsst.pipe.base.Struct`
    with the following fields:

    - ``wcs`` :  the fit WCS (`lsst.afw.geom.SkyWcs`)
    - ``scatterOnSky`` :  median on-sky separation between reference
      objects and sources in "matches" (`lsst.afw.geom.Angle`)

Definition at line 81 of file fitTanSipWcs.py.

◆ initialWcs()

lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask.initialWcs ( self,
matches,
wcs )
Generate a guess Wcs from the astrometric matches

We create a Wcs anchored at the center of the matches, with the scale
of the input Wcs.  This is necessary because matching returns only
matches with no estimated Wcs, and the input Wcs is a wild guess.
We're using the best of each: positions from the matches, and scale
from the input Wcs.

Parameters
----------
matches : `list` of `lsst.afw.table.ReferenceMatch`
    List of sources matched to references.
wcs : `lsst.afw.geom.SkyWcs`
    Current WCS.

Returns
-------
newWcs : `lsst.afw.geom.SkyWcs`
    Initial WCS guess from estimated crpix and crval.

Definition at line 182 of file fitTanSipWcs.py.

◆ plotFit()

lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask.plotFit ( self,
matches,
wcs,
rejected )
Plot the fit

We create four plots, for all combinations of (dx, dy) against
(x, y).  Good points are black, while rejected points are red.

Parameters
----------
matches : `list` of `lsst.afw.table.ReferenceMatch`
    List of sources matched to references.
wcs : `lsst.afw.geom.SkyWcs`
    Fitted WCS.
rejected : array-like of `bool`
    Array of matches rejected from the fit.

Definition at line 262 of file fitTanSipWcs.py.

◆ rejectMatches()

lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask.rejectMatches ( self,
matches,
wcs,
rejected )
Flag deviant matches

We return a boolean numpy array indicating whether the corresponding
match should be rejected.  The previous list of rejections is used
so we can calculate uncontaminated statistics.

Parameters
----------
matches : `list` of `lsst.afw.table.ReferenceMatch`
    List of sources matched to references.
wcs : `lsst.afw.geom.SkyWcs`
    Fitted WCS.
rejected : array-like of `bool`
    Array of matches rejected from the fit. Unused.

Returns
-------
rejectedMatches : `ndarray` of type `bool`
    Matched objects found to be outside of tolerance.

Definition at line 235 of file fitTanSipWcs.py.

Member Data Documentation

◆ _DefaultName

str lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask._DefaultName = "fitTanSipWcs"
staticprotected

Definition at line 78 of file fitTanSipWcs.py.

◆ ConfigClass

lsst.meas.astrom.fitTanSipWcs.FitTanSipWcsTask.ConfigClass = FitTanSipWcsConfig
static

Definition at line 77 of file fitTanSipWcs.py.


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