Agenda Changes: ImageDM discussion during Education I
François Bonnarel
francois.bonnarel at astro.unistra.fr
Tue Jun 4 06:54:04 PDT 2013
No harm Arnold, I think.
The discussion on ImageDM is far from being closed. It's just starting
actually!
What do you think of the proposed utypes and of the Custom
AstroCoordinateSystem argument ?
Cheers
François
Le 04/06/2013 15:48, Rots, Arnold a écrit :
> I suppose I was - but I heard or saw no announcement of when and where
> this was
> going to happen and no one told me. There was a glaring lack of
> communication.
>
> - Arnold
>
>
> On Tue, Jun 4, 2013 at 5:15 AM, François Bonnarel
> <francois.bonnarel at astro.unistra.fr
> <mailto:francois.bonnarel at astro.unistra.fr>> wrote:
>
> Hi Arnold,Hi everybody,
> Le 17/05/2013 09:46, Rots, Arnold a écrit :
>
> I presented these two alternatives for an open discussion. But you
> were in another room !!!
>
> Best regards
> François
>
>
> -------------------------------------------------------------------------------------------------------------
> 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 <mailto:arots at cfa.harvard.edu>
> USA http://hea-www.harvard.edu/~arots/
> <http://hea-www.harvard.edu/%7Earots/>
> --------------------------------------------------------------------------------------------------------------
>
>
>
> On Tue, Jun 4, 2013 at 5:15 AM, François Bonnarel
> <francois.bonnarel at astro.unistra.fr
> <mailto:francois.bonnarel at astro.unistra.fr>> wrote:
>
> Hi Arnold,Hi everybody,
> Le 17/05/2013 09:46, Rots, Arnold a écrit :
>> Since that session was not really completed (or, if it did,
>> I wasn't able to find out where and when), I posted some
>> comments on the DM sessions Twiki page, in the form of
>> some slides regarding the implementation of WCS in STC.
>> You may recall that Francois asserted that there was no
>> such support.
> This is not true. I said it could be difficult or heavy in the
> first DAL session. But I didn't say there was no support. In the
> small Image DM session I presented slides (there are on the DM
> Heidelberg session page) where I proposed STC utypes for the ref
> pos and the CDmatrix and projection. I identified Cart2DRefFrame
> as the package to do that. And I also identified PixelCoordSystem
> as the package able to describe the Reference pixel (CRPIX). I
> didn't notice your slides at that moment, sorry. Below I discuss
> your example in term of ImageDM utypes (path utypes) to be used in
> DAL services query responses.
>
>> There is; see: table 4, Appendix A, and the
>> example in Appendix B.2.
>> The main issue is that STC data model was designed to provide a
>> characterization of the data it referred to along its coordinates.
>> Part of that was the WCS projection.
>> When the characterization role is rejected and one starts
>> cherry-picking pieces from the data model, it becomes more
>> difficult to put the WCS information back in, since the integrity
>> of the data model has been lost.
>> To be blunt: the WCS support is there, but the way you choose
>> to use STC may make it very difficult to take advantage of it.
> If we think to provide WCS (or Mapping) for an image along the
> lines of the example in your slides what would be the utypes ?
> I found those with their equivalent WCS FITS Keywords
> PixelCoordSystem.PixelCoordFrame.Cart2DrefFrame.projection --->
> second part of CTYPE
> PixelCoordSystem.PixelCoordFrame.Cart2DrefFrame.Transform2 ---->
> "CDELT" keywords
> PixelCoordSystem.PixelCoordFrame.CoordRefPos.Vector2DCoordinate
> ----> "CRVAL" Keywords
> PixelCoordSystem.PixelCoordFrame.CARTESIAN.naxes ----> NAXES
> PixelCoordSystem.PixelCoordFrame.ReferencePixel.Pixel2D.Name1
> ----> First part of CTYPE1
> PixelCoordSystem.PixelCoordFrame.ReferencePixel.Pixel2D.Name2
> -----> First part of CTYPE2
> PixelCoordSystem.PixelCoordFrame.ReferencePixel.Pixel2D.Value2
> ------> CRPIX Keywords
>
> Of course this works. The STC/WCS solution I had in mind was a
> little different because WCS is actually at least a two step
> transformation
> Sphere ------> projected plane (Wolrld coordinates to
> "standard" coordinates)
> projected plane ----> pixel plane
> I thought the first transformation is best rendered SEMANTICALLY
> by a real AstroCoordSystem with a Custom Cart2DSpaceRefFrame and a
> Custom RefPos. These features do not really belong to Pixel space
> in my sense.
> Then the second transformation (using the matrix/CDELT Transform2
> and Pixel reference position) could be rendered by the
> PixelCoordinateSystem
>
> Alternatively I also proposed the Mapping stuff as it is done in
> the ImageDM draft. Something much closer the organisation of WCS
> keywords like
>
> Mapping.CoordRefPixel
> Mapping.CDmatrix
> Mapping.Projection
> etc...
>
>
> I presented these two alternatives for an open discussion. But you
> were in another room !!!
>
> Best regards
> François
>
>>
>> Cheers,
>>
>> - Arnold
>>
>>
>> On Mon, May 13, 2013 at 1:24 PM, Jesus Salgado
>> <jsalgado at sciops.esa.int <mailto:jsalgado at sciops.esa.int>> wrote:
>>
>> Dear all,
>>
>> Massimo Ramella has kindly provided part of the time of his
>> Education 1 session on
>> Thursday 11:00–12:30 to finish the discussion on ImageDM
>> draft that we were having
>> during DM1 session.
>>
>> That means, we will have F. Bonnarel presentation that could
>> not give today plus
>> the brainstorming.
>>
>> Please take note of that :)
>> Cheers,
>> Jesus
>>
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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 <tel:617%20495%207356>
>> Cambridge, MA 02138 arots at cfa.harvard.edu
>> <mailto:arots at cfa.harvard.edu>
>> USA http://hea-www.harvard.edu/~arots/
>> <http://hea-www.harvard.edu/%7Earots/>
>> --------------------------------------------------------------------------------------------------------------
>>
>
>
>
>
>
> --
> -------------------------------------------------------------------------------------------------------------
> 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 <mailto:arots at cfa.harvard.edu>
> USA http://hea-www.harvard.edu/~arots/
> <http://hea-www.harvard.edu/%7Earots/>
> --------------------------------------------------------------------------------------------------------------
>
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