Class WCS

  • All Implemented Interfaces:
    java.io.Serializable, Component

    public class WCS
    extends Converter
    A World Coordinate System defines a translation between celestial and pixel coordinates. Note that in many cases FITS keywords describe the transformations in the other direction (from pixel to celestial) but we follow the convention that forward transformations are from celestial to pixel. Given a WCS object, wcs, the pixel-celestial coordinates trasnformation is simply wcs.inverse();
    See Also:
    Serialized Form
    • Method Detail

      • setPreferDSS

        public static void setPreferDSS​(boolean flag)
      • getCoordinateSystem

        public CoordinateSystem getCoordinateSystem()
        Get the CoordinateSystem used in the WCS
      • getProjection

        public Projection getProjection()
        Get the projection used in the WCS
      • getScaler

        public Scaler getScaler()
        Get the linear scaler used in the projection
      • getDistorter

        public Distorter getDistorter()
        Get the plane distorter used in the projection (or null)
      • standardWCS

        public boolean standardWCS()
      • getHeaderNaxis

        public int[] getHeaderNaxis()
      • setHeaderNaxis

        public void setHeaderNaxis​(int[] newAxes)
      • getScale

        public double getScale()
        Get the nominal scale of the WCS.
      • updateHeader

        public void updateHeader​(nom.tam.fits.Header h,
                                 Scaler s,
                                 double[] crval,
                                 java.lang.String projString,
                                 java.lang.String coordString)
                          throws java.lang.Exception
        Write FITS WCS keywords given key values. Only relatively simple WCSs are handled here. We assume we are dealing with axes 1 and 2.
        Parameters:
        h - The header to be updated.
        s - A Scaler giving the transformation between standard projection coordinates and pixel/device coordinates.
        projString - A three character string giving the projection used. Supported projections are: "Tan", "Sin", "Ait", "Car", "Zea".
        coordString - A string giving the coordinate system used. The first character gives the general frame. For most frames the remainder of the string gives the equinox o the coordinate system. E.g., J2000, B1950, Galactic, "E2000", "H2020.10375".
        Throws:
        java.lang.Exception
      • copyToHeader

        public void copyToHeader​(nom.tam.fits.Header h)
                          throws nom.tam.fits.HeaderCardException
        Throws:
        nom.tam.fits.HeaderCardException
      • approximate

        public WCS approximate​(double[] pix)
                        throws TransformationException
        Approximate a WCS (which presumably includes a Distorter) with a standard, locally correct, WCS.
        Parameters:
        pix - The pixel location we want to approximate around.
        Returns:
        A more standard WCS with the distortion removed (locally).
        Throws:
        TransformationException