lsst.afw g4d73512994+c357e897d2
|
Classes | |
class | BoxGrid |
class | FrameSetInfo |
class | PermutedFrameSet |
class | TransformTestBaseClass |
Functions | |
def | makeSipPolyMapCoeffs (metadata, name) |
def | makeSipIwcToPixel (metadata) |
def | makeSipPixelToIwc (metadata) |
def lsst.afw.geom.testUtils.makeSipIwcToPixel | ( | metadata | ) |
Make an IWC to pixel transform with SIP distortion from FITS-WCS metadata This function is primarily intended for unit tests. IWC is intermediate world coordinates, as described in the FITS papers. Parameters ---------- metadata : lsst.daf.base.PropertySet FITS metadata describing a WCS with inverse SIP coefficients Returns ------- lsst.afw.geom.TransformPoint2ToPoint2 Transform from IWC position to pixel position (zero-based) in the forward direction. The inverse direction is not defined. Notes ----- The inverse SIP terms APn_m, BPn_m are polynomial coefficients x^n y^m for computing transformed x, y respectively. If we call the resulting polynomial inverseSipPolynomial, the returned transformation is: pixelPosition = pixel origin + uv + inverseSipPolynomial(uv) where uv = inverseCdMatrix * iwcPosition
Definition at line 196 of file testUtils.py.
def lsst.afw.geom.testUtils.makeSipPixelToIwc | ( | metadata | ) |
Make a pixel to IWC transform with SIP distortion from FITS-WCS metadata This function is primarily intended for unit tests. IWC is intermediate world coordinates, as described in the FITS papers. Parameters ---------- metadata : lsst.daf.base.PropertySet FITS metadata describing a WCS with forward SIP coefficients Returns ------- lsst.afw.geom.TransformPoint2ToPoint2 Transform from pixel position (zero-based) to IWC position in the forward direction. The inverse direction is not defined. Notes ----- The forward SIP terms An_m, Bn_m are polynomial coefficients x^n y^m for computing transformed x, y respectively. If we call the resulting polynomial sipPolynomial, the returned transformation is: iwcPosition = cdMatrix * (dxy + sipPolynomial(dxy)) where dxy = pixelPosition - pixelOrigin
Definition at line 235 of file testUtils.py.
def lsst.afw.geom.testUtils.makeSipPolyMapCoeffs | ( | metadata, | |
name | |||
) |
Return a list of ast.PolyMap coefficients for the specified SIP matrix The returned list of coefficients for an ast.PolyMap that computes the following function: f(dxy) = dxy + sipPolynomial(dxy)) where dxy = pixelPosition - pixelOrigin and sipPolynomial is a polynomial with terms `<name>n_m for x^n y^m` (e.g. A2_0 is the coefficient for x^2 y^0) Parameters ---------- metadata : lsst.daf.base.PropertySet FITS metadata describing a WCS with the specified SIP coefficients name : str The desired SIP terms: one of A, B, AP, BP Returns ------- list A list of coefficients for an ast.PolyMap that computes the specified SIP polynomial, including a term for out = in Note ---- This is an internal function for use by makeSipIwcToPixel and makeSipPixelToIwc
Definition at line 141 of file testUtils.py.