VOEvent 1.1 new draft with STC elaboration

[Arnold Rots]

Roy,

Thank for putting it together.  But since you departed from my draft,
I do have some corrections :-)

3.4 1st para: "interprested" -> "interpreted"

3.4.1 The first four lines of the last example should read:

  <ObservatoryLocation id="'y'">
    <AstroCoordSystem id="TT-GEOD-TOPO" xlink:type="simple"
        xlink:href="ivo://STClib/CoordSys#TT-GEOD-TOPO"/>
    <AstroCoords coord_system_id="TT-GEOD-TOPO">

(or make it UTC, if you like, but you do need GEOD).
I suspect that 118.09 should really be 241.91 and I am deeply
suspicious about Palomar's being at an altitude of 218 m.
If you're not sure, use the KPNO example (and change the href):
          <C1 pos_unit="deg">248.4056</C1>
          <C2 pos_unit="deg">31.9586</C2>
          <C3 pos_unit="m">2158</C3>

3.4.2 Although your explanation is practical, it may be helpful to
    explain how it works:
The AstroCoords are tied by a coord_system_id (="UTC-FK5-TOPO") to an
    AstroCoordSystem that has been tagged by an identical id
    attribute, and that points to a coordinate system definition in a
    library through the xlink:href attribute; that library contains
    the full description of the coordinate system.
    Clearly, coord_system_id needs to be identical to id, although
    they could use any arbitrary string to communicate with each
    other.  However, for clarity we will adopt a convention where this
    id string will be identical to the last part of the xlink:href.

"ion that order" -> "in that order"

However, one of the assumptions in all this is that the reference
location (origin) for space and time are the same.
That means that one should really only allow BARY to be used in
conjunction with TDB.
So, you end up with 10 systems: TT/UTC-ICRS/FK5-TOPO/GEO and
TDB-ICRS/FK5-BARY; I am glossing over the issue that one would really
want to know whether DE-201 or DE-405 is used for TDB-BARY.

3.4.3  "eg" -> "e.g.,"
I think this needs text to explain that if clients are not interested
in positions with mas accuracy (and most errors won't be that small
anyway), they will want to accept FK5 as well as ICRS.  If timing
accuray is longer than minutes, they don't care about UTC or TT.
The timing difference between TOPO and GEO will be of the order of ms,
between TT/UTC and TDB 500 s.

I still have misgivings about you pseudocode, but it may help to
explain that the working of this piece of code depends on (1) there
being only one set of coordinates and (2) adherence to the id naming
convention in 3.4.2.

  - Arnold

Roy Williams wrote:
> A new version of the VOEvent 1.1 working draft is uploaded to the Twiki
> 
> http://www.ivoa.net/internal/IVOA/IvoaVOEvent/VOEvent-v1.1-060508.html
> 
> This version has an elaboration of usage of the IVOA Space-Time  
> Coordinates (STC) system, thank-you from all of us to Arnold Rots. As  
> always, your comments are appreciated. This may be the last  
> opportunity for significant schema change.
> 
> Roy Williams
> 
> 
> 
> 
> On May 1, 2006, at 4:16 PM, Roy Williams wrote:
> 
> > Dear VOEvent
> >
> > I have been taking the lead on editing the specification document  
> > for VOEvent packets, and I would appreciate your eagle eyes reading  
> > and commenting. We hope to present this draft of VOEvent 1.1 to the  
> > IVOA meeting next month, and for this to be essentially the final  
> > definition, so we can move on with implementation, move on to  
> > building GCN2 based on this. So speak now or forever hold your peace!
> >
> > Thank you for your invaluable help
> >
> > Roy Williams
> > ----------------------------------
> >
> > The VOEvent definition is here:
> > http://www.ivoa.net/internal/IVOA/IvoaVOEvent/VOEvent-v1.1-060501.html
> >
> > And the accompanying draft schema is here:
> > http://www.ivoa.net/internal/IVOA/IvoaVOEvent/VOEvent-v1.1-060425.xsd
> >
> > Here is a summary of the deltas from the 1.0 specification:
> > -- definition of roles in transport network as Author, Publisher,  
> > Repository, Subscriber, and Relay/Broker/Filter
> > -- exposition of the interaction of VOEvent with VO registry;  
> > registration of Event, Author, Publisher and Repository.
> > -- event identifier is actually two identifiers, concatenation of  
> > publisher id and event label
> > -- clear adoption of  VO SpaceTime Coordinates for position/time,  
> > recommended parsing usage
> > -- curation metadata lined up with VO registry curation -- an  
> > Author is a registered organization
> > -- the Concept element redefined to hold controlled vocabulary to  
> > describe nature of event
> >
> >
> >
> >
> > California Institute of Technology
> > 626 395 3670
> >
> >
> >
> 
> California Institute of Technology
> 626 395 3670
> 
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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 head.cfa.harvard.edu
USA                                     http://hea-www.harvard.edu/~arots/
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