[ImageDM] Mapping

[Arnold Rots]

In principle we have solved that by distinguishing the redshift/Doppler
coordinate
from the spectral coordinate.
The different restfrequencies would then correspond to different pixels
along the
spectral axis.

  - Arnold

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Arnold H. Rots                                          Chandra X-ray
Science Center
Smithsonian Astrophysical Observatory                   tel:  +1 617 496
7701
60 Garden Street, MS 67                                      fax:  +1 617
495 7356
Cambridge, MA 02138
arots at cfa.harvard.edu
USA
http://hea-www.harvard.edu/~arots/
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On Thu, Nov 21, 2013 at 11:20 AM, Peter Teuben <teuben at astro.umd.edu> wrote:

> On 11/21/2013 10:23 AM, Tim Jenness wrote:
> > On Nov 20, 2013, at 15:38 , CresitelloDittmar, Mark <
> mdittmar at cfa.harvard.edu> wrote:
> >
> >>
> >> 3) Can you give an example of the content for "Mapping.AxisMap"?
> >>     Say I have an image with WCS ("RA", "DEC", "Time"), pixel axes (#1,
> #2, #3) plus value
> >>     The 'Linear' portion is applied (CD matrix) to (#1, #2, #3)
> producing intermediate axes.
> >>     a) do these have names?
> >>
> >>     AxisMap (pg 29) "is used to map the axes of the intermediate world
> coordinates (i.e., after the CD or PC transform, which may transpose or
> rotate the image axes) to the axes of
> >> the final world coordinate system.
> >>
> > Do I get the impression that the VO WCS model is entirely based on the
> FITS WCS model? Has there been any thought to having a more flexible model
> that can, for example, support chained mappings (as implemented in the AST
> library and internally by HST)? Can the model support an IFU? Or a
> radio-style “channel map”?
> >
> > —
> > Tim Jenness
> >
>
> Related to Mark's comment on allowing having multiple instances of
> Mapping, I can imagine the use case in the spectral domain, where a data
> cube (channel maps) get a different doppler velocity depending on what
> reference line you pick. A very common thing in modern day ALMA and JVLA
> datasets.
>
> peter
>
>
>
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