Description:
This function finds values that resemble the the FITS keywords CRVAL1/2/3..,
CRPIX1/2/3..., CRDELT1/2/3... and CROTA2, on the assumption that the base Frame in the supplied
FrameSet describe GRID coords (i.e. FITS pixel coords), and the current Frame describe the required
WCS. It is not restricted to 2D FrameSets.
If the FrameSet can be written to a FitsChan successfully using FITS-WCS encoding, the
the resulting keyword values are returned. Otherwise, the values are estimated by
transforming closely spaced pixel positions along each axis. If the current Frame contains
a SkyFrame, and the SkyFrame has a defined reference position, then this position
specifies the returned CRVAL values. Otherwise, the reference position is assumed to be at
the central pixel.
Invocation
CALL ATL_GETPIXELPARAMS( FSET, DIMS, DEGS, CRPIX,
CRVAL, CDELT, CROTA, STATUS )
Arguments
FSET = INTEGER (Given)
The FrameSet.
DIMS()
= INTEGER (Given)
An array supplied holding the number of pixels along each edge of the pixel
array. The number of elements in this array should match the number of axes in the base Frame of
FSET.
DEGS = LOGICAL (Given)
If .TRUE., then the CRVAL, CDELT and CROTA values
for sky axes are returned in units of degrees. Otherwise they are returned in radians.
CRPIX() =
DOUBLE PRECISION (Returned)
An array returned holding the position of the reference pixel in the base
Frame of FSET. The number of elements in this array should match the number of axes in the base Frame of
FSET.
CRVAL()
= DOUBLE PRECISION (Returned)
An array returned holding the position of the reference pixel in the current
Frame of FSET. The number of elements in this array should match the number of axes in the current Frame of
FSET.
CDELT()
= DOUBLE PRECISION (Returned)
An array returned holding the geodesic distance along each edge
of the reference pixel, measured within the current Frame of FSET. The number of elements in this
array should match the number of axes in the base Frame of FSET.
CROTA = DOUBLE PRECISION
(Returned)
The angle from north in the current frame of FSET to the second spatial pixel axis,
measured positive through east. This will be returned set to AST__BAD if the current frame of FSET
does not contain a SkyFrame.
STATUS = INTEGER (Given and Returned)
The global status.