- All Implemented Interfaces:
public class SIP extends Distorter
Implement the SIP convention for distorting a standard projection. The SIP distortion as defined in the FITS headers takes place after the CD matrix has been applied to the data which makes it happen later than the other distorters. The applyBeforeScaling method is defined to return false for this scaler. Note that although the CD matrix is applied, the CRPIX offset is not. In principle it would be possible to adjust the coefficients so that the distortion took place before the scaling but we have chosen to mimic the approach used in the SIP definition.
- See Also:
- Serialized Form
Nested Class Summary
Nested Classes Modifier and Type Class Description
SIP.SIPinverseCreate the inverse distorter for the main class here.
Modifier and Type Method Description
getDescription()What does this object do?
getName()A name for this object
inverse()Get the inverse of the transformation.
isInverse(Transformer trans)Is another transformer the inverse of this one? True only if it was created as the inverse of this transformation.
transform(double in, double out)Calculate the distorted (actual pixel) coordinates given the standard coordinates.
Methods inherited from class skyview.geometry.Distorter
getInputDimension, getOutputDimension, jacobian
public SIP(nom.tam.fits.Header h)Create a distorter from a FITS header. We will look for A_ORDER, B_ORDER, A_n_m and B_n_m keywords. If AP_ORDER and BP_ORDER are found and the SIPNumericInversion setting is not found, then we will also look for AP_n_m and BP_n_m for the inverse distortion.
public SIP(double distortx, double distorty, double undistortx, double undistorty)Explicitly set the coefficients for the distorter. We infer the order from the input arrays. If the undistort's arguments are given we assume that the user wishes to use the inverse distortion. If null then we use numerical inversion of the distortion.
public java.lang.String getName()Description copied from class:
DistorterA name for this object
public java.lang.String getDescription()Description copied from class:
DistorterWhat does this object do?
public Distorter inverse()Description copied from class:
TransformerGet the inverse of the transformation. If the order matters, then the inverse is to be applied after the original transformation. This is primarily an issue with Converters.
public boolean applyBeforeScaling()
public void transform(double in, double out)Calculate the distorted (actual pixel) coordinates given the standard coordinates. Note that the coefficients only give the distortion, so we need to add in the inputs. Note that primary transformations defined in SIP go the other way. Given an actual pixel location, they give the a sky position in the undistorted plane.
public boolean isInverse(Transformer trans)Is another transformer the inverse of this one? True only if it was created as the inverse of this transformation.
public static void main(java.lang.String args)