Welcome to the Harris Geospatial product documentation center. Here you will find reference guides, help documents, and product libraries.




  This procedure converts from (a,d,v) sky coordinates to (x,y,z)
  pixel coordinates in a data cube. It is a wrapper to ad2xy in the
  IDL Astronomy User's Library, which does not handle 3D data.


  head: A fits header. String array
  a: List of sky x coordinates (alpha, lon). Scalar or vector
  d: List of sky y coordinates (dec, lat). Scalar or vector
  v: List of sky z coordinates (velocity, freq). Scalar or vector.

Keyword Parameters

  ortho: Set this keyword if the third axis of the input coordinates
        is orthogonal to the first two; that is, if adv describe a
        cube, where a and d are constant across the cube. When this
        is true, the computation can be performed more quickly.


  x: Pixel x coordinates. These are zero-indexed, IDL style.
  y: Pixel y coordinates
  z: Pizel z coordinates


  This function calls ad2xy, and hence can handle any wcs stuff that
  that procedure can. The only restriction is that the fits header
  have a simple description for transforming from v->z. That is,
  CDELT3/CD3_3, CRPIX3, CRVAL3, keywords should completely define the
  transformation. This is almost always the case.

Modification History

  March 2010: Written by Chris Beaumont
  May 2010: Fixed a bug in call to ad2xy. cnb.
  Sep 2010: Fixed a bug when testing whether head is a string
            array. cnb.
  June 2011: Optimized for the case where a,d,v describe a cube with
            a,d constant along slices. Added ortho keyword. cnb.

© 2017 Exelis Visual Information Solutions, Inc. |  Legal
My Account    |    Buy    |    Contact Us