LSST Applications  21.0.0+c4f5df5339,21.0.0+e70536a077,21.0.0-1-ga51b5d4+7c60f8a6ea,21.0.0-10-g560fb7b+411cd868f8,21.0.0-10-gcf60f90+8c49d86aa0,21.0.0-13-gc485e61d+38156233bf,21.0.0-16-g7a993c7b9+1041c3824f,21.0.0-2-g103fe59+d9ceee3e5a,21.0.0-2-g1367e85+0b2f7db15a,21.0.0-2-g45278ab+e70536a077,21.0.0-2-g5242d73+0b2f7db15a,21.0.0-2-g7f82c8f+feb9862f5e,21.0.0-2-g8f08a60+9c9a9cfcc8,21.0.0-2-ga326454+feb9862f5e,21.0.0-2-gde069b7+bedfc5e1fb,21.0.0-2-gecfae73+417509110f,21.0.0-2-gfc62afb+0b2f7db15a,21.0.0-3-g21c7a62+a91f7c0b59,21.0.0-3-g357aad2+062581ff1a,21.0.0-3-g4be5c26+0b2f7db15a,21.0.0-3-g65f322c+85aa0ead76,21.0.0-3-g7d9da8d+c4f5df5339,21.0.0-3-gaa929c8+411cd868f8,21.0.0-3-gc44e71e+fd4029fd48,21.0.0-3-ge02ed75+5d9b90b8aa,21.0.0-38-g070523fc+44fda2b515,21.0.0-4-g591bb35+5d9b90b8aa,21.0.0-4-g88306b8+3cdc83ea97,21.0.0-4-gc004bbf+d52368b591,21.0.0-4-gccdca77+a5c54364a0,21.0.0-5-g7ebb681+81e2098694,21.0.0-5-gdf36809+87b8d260e6,21.0.0-6-g2d4f3f3+e70536a077,21.0.0-6-g4e60332+5d9b90b8aa,21.0.0-6-g5ef7dad+3f4e29eeae,21.0.0-7-gc8ca178+0f5e56d48f,21.0.0-9-g9eb8d17+cc2c7a81aa,master-gac4afde19b+5d9b90b8aa,w.2021.07
LSST Data Management Base Package
Functions
lsst.afw.geom.wcsUtils.wcsUtilsContinued Namespace Reference

Functions

def getSipMatrixFromMetadata (metadata, name)
 
def computePixelToDistortedPixel (pixelToFocalPlane, focalPlaneToFieldAngle)
 

Function Documentation

◆ computePixelToDistortedPixel()

def lsst.afw.geom.wcsUtils.wcsUtilsContinued.computePixelToDistortedPixel (   pixelToFocalPlane,
  focalPlaneToFieldAngle 
)
Compute the transform ``pixelToDistortedPixel``, which applies optical
distortion specified by ``focalPlaneToFieldAngle``.

The resulting transform is designed to be used to convert a pure TAN WCS
to a WCS that includes a model for optical distortion. In detail,
the initial WCS will contain these frames and transforms::

    PIXELS frame -> pixelToIwc -> IWC frame ->  gridToIwc -> SkyFrame

To produce the WCS with distortion, replace ``pixelToIwc`` with::

    pixelToDistortedPixel -> pixelToIwc

Parameters
----------
pixelToFocalPlane : `lsst.afw.geom.TransformPoint2ToPoint2`
    Transform parent pixel coordinates to focal plane coordinates
focalPlaneToFieldAngle : `lsst.afw.geom.TransformPoint2ToPoint2`
    Transform focal plane coordinates to field angle coordinates

Returns
-------
pixelToDistortedPixel : `lsst.afw.geom.TransformPoint2ToPoint2`
    A transform that applies the effect of the optical distortion model.

Definition at line 61 of file wcsUtilsContinued.py.

61 def computePixelToDistortedPixel(pixelToFocalPlane, focalPlaneToFieldAngle):
62  """Compute the transform ``pixelToDistortedPixel``, which applies optical
63  distortion specified by ``focalPlaneToFieldAngle``.
64 
65  The resulting transform is designed to be used to convert a pure TAN WCS
66  to a WCS that includes a model for optical distortion. In detail,
67  the initial WCS will contain these frames and transforms::
68 
69  PIXELS frame -> pixelToIwc -> IWC frame -> gridToIwc -> SkyFrame
70 
71  To produce the WCS with distortion, replace ``pixelToIwc`` with::
72 
73  pixelToDistortedPixel -> pixelToIwc
74 
75  Parameters
76  ----------
77  pixelToFocalPlane : `lsst.afw.geom.TransformPoint2ToPoint2`
78  Transform parent pixel coordinates to focal plane coordinates
79  focalPlaneToFieldAngle : `lsst.afw.geom.TransformPoint2ToPoint2`
80  Transform focal plane coordinates to field angle coordinates
81 
82  Returns
83  -------
84  pixelToDistortedPixel : `lsst.afw.geom.TransformPoint2ToPoint2`
85  A transform that applies the effect of the optical distortion model.
86  """
87  # return pixelToFocalPlane -> focalPlaneToFieldAngle -> tanFieldAngleToocalPlane -> focalPlaneToPixel
88  focalPlaneToTanFieldAngle = makeTransform(linearizeTransform(focalPlaneToFieldAngle,
89  lsst.geom.Point2D(0, 0)))
90  return pixelToFocalPlane.then(focalPlaneToFieldAngle) \
91  .then(focalPlaneToTanFieldAngle.inverted()) \
92  .then(pixelToFocalPlane.inverted())
def computePixelToDistortedPixel(pixelToFocalPlane, focalPlaneToFieldAngle)
std::shared_ptr< TransformPoint2ToPoint2 > makeTransform(lsst::geom::AffineTransform const &affine)
Wrap an lsst::geom::AffineTransform as a Transform.
lsst::geom::AffineTransform linearizeTransform(TransformPoint2ToPoint2 const &original, lsst::geom::Point2D const &inPoint)
Approximate a Transform by its local linearization.

◆ getSipMatrixFromMetadata()

def lsst.afw.geom.wcsUtils.wcsUtilsContinued.getSipMatrixFromMetadata (   metadata,
  name 
)
Extract a SIP matrix from FITS TAN-SIP WCS metadata.

Omitted coefficients are set to 0 and all coefficients may be omitted.

Parameters
----------
metadata : `lsst.daf.base.PropertySet`
    FITS metadata.
name : `str`
    Name of TAN-SIP matrix (``"A"``, ``"B"``, ``"Ap"``, or ``"Bp"``).

Returns
-------
`numpy.array`
    The SIP matrix.

Raises
------
TypeError
    If the order keyword ``<name>_ORDER`` (e.g. ``AP_ORDER``) is not found,
    the value of the order keyword cannot be read as an integer,
    the value of the order keyword is negative,
    or if a matrix parameter (e.g. ``AP_5_0``) cannot be read as a float.

Definition at line 30 of file wcsUtilsContinued.py.

30 def getSipMatrixFromMetadata(metadata, name):
31  """Extract a SIP matrix from FITS TAN-SIP WCS metadata.
32 
33  Omitted coefficients are set to 0 and all coefficients may be omitted.
34 
35  Parameters
36  ----------
37  metadata : `lsst.daf.base.PropertySet`
38  FITS metadata.
39  name : `str`
40  Name of TAN-SIP matrix (``"A"``, ``"B"``, ``"Ap"``, or ``"Bp"``).
41 
42  Returns
43  -------
44  `numpy.array`
45  The SIP matrix.
46 
47  Raises
48  ------
49  TypeError
50  If the order keyword ``<name>_ORDER`` (e.g. ``AP_ORDER``) is not found,
51  the value of the order keyword cannot be read as an integer,
52  the value of the order keyword is negative,
53  or if a matrix parameter (e.g. ``AP_5_0``) cannot be read as a float.
54  """
55  arr = _getSipMatrixFromMetadata(metadata, name)
56  if arr.shape == (): # order=0
57  arr.shape = (1, 1)
58  return arr
59 
60