Fwd: [nvo-techwg] re: Reading source lists

[Rob Seaman]

Seemed pertinent whenever the STC wrangling start up again:

Begin forwarded message:

> From: Arnold Rots <arots at head.cfa.harvard.edu>
> Date: August 30, 2007 11:55:22 AM MST
> To: Doug Tody <dtody at nrao.edu>
> Cc: jcm at head.cfa.harvard.edu, NVO Technical Working Group  
> <techwg at us-vo.org>, Arnold Rots <arots at head.cfa.harvard.edu>
> Subject: Re: [nvo-techwg] re: Reading source lists
>
> Yes, that is true, though it was somewhat laborious since the STC
> schema is not imported into VOTable.
> You could consider this schema as providing something like a
> VOTable-light, especially suitable for coordinate information, though
> it would also handle time series data quite well; and, come to think
> of it, spectra.
> The advantage of this one is that the coordinate metadata are easier
> to specify.
> Anyway, I wanted to show that it is quite simple to create small
> custom schemata based on STC.
>
>   - Arnold
>
> Doug Tody wrote:
>> Hi Arnold -
>>
>> I recall some discussion of an STC-based COORDSYS replacement in the
>> VOTable WG in Beijing.  This might allow a standard generic table
>> mechanism such as VOTable, to be used in conjunction with STC-defined
>> coordinate systems.  Basically VOTable would provide the table of
>> coordinates in a standard table form, but the STC metadata would
>> define the coordinate system.  Is this a possible alternative?
>>
>> 	- Doug
>>
>>
>> On Thu, 30 Aug 2007, Arnold Rots wrote:
>>
>>> Roy,
>>>
>>> I think I have a better way to specify your item 2.
>>> I fear you are going to dislike this, but we can do this in a simple
>>> way, with all the hooks for future expansion (to other coordinate
>>> systems, etc.) built in, since now have an almost-standard on
>>> coordinate systems ;-)
>>>
>>> I just put together a minischema that allows one to build a table of
>>> coordinate positions, using the metadata structure of STC.
>>>
>>> An example document that employs this schema is appended.
>>> The point is, we have the infrastructure that STC provides and can
>>> take advantage of it in a pretty simple way to create VO documents
>>> that allow exchange of coordinate information with full metadata.
>>> Can I make you like it?
>>>
>>>   - Arnold
>>>
>>> -------------------------------------------------------------------- 
>>> ------
>>> 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/
>>> -------------------------------------------------------------------- 
>>> ------
>>>
>>> PositionList.xml:
>>>
>>>
>>> <?xml version="1.0" encoding="UTF-8"?>
>>>   <!--  The STC metadata to describe a list of ICRS positions  -->
>>> <PositionList xmlns="PL.xsd"
>>>     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>>>     xsi:schemaLocation="PL.xsd http://hea-www.harvard.edu/~arots/ 
>>> nvometa/v1.30/PL.xsd">
>>>   <CatalogEntryLocation xmlns="http://www.ivoa.net/xml/STC/stc- 
>>> v1.30.xsd"
>>>     xmlns:xlink="http://www.w3.org/1999/xlink"
>>>     xsi:schemaLocation="http://www.ivoa.net/xml/STC/stc-v1.30.xsd
>>>       stc-v1.30.xsd">
>>>       <!--  Specify the ICRS frame, referenced to the barycenter   
>>> -->
>>>     <AstroCoordSystem id="ICRS">
>>>       <SpaceFrame>
>>>         <ICRS/>
>>>         <BARYCENTER/>
>>>         <SPHERICAL coord_naxes="2"/>
>>>       </SpaceFrame>
>>>     </AstroCoordSystem>
>>>     <AstroCoords coord_system_id="ICRS">
>>>       <Position2D unit="deg">
>>>         <Name>RA,Dec</Name>
>>>         <Value2>
>>>           <C1 xsi:nil="true" idref="RA"/>
>>>           <C2 xsi:nil="true" idref="Dec"/>
>>>         </Value2>
>>>       </Position2D>
>>>     </AstroCoords>
>>>   </CatalogEntryLocation>
>>>   <Table>
>>>     <Header>
>>>       <TH id="RA">RA</TH> <TH id="Dec">Dec</TH> </Header>
>>>     <TR><TD>123.4</TD><TD>56.7</TD></TR>
>>>     <TR><TD>133.4</TD><TD>46.7</TD></TR>
>>>     <TR><TD>143.4</TD><TD>36.7</TD></TR>
>>>     <TR><TD>153.4</TD><TD>26.7</TD></TR>
>>>     <TR><TD>163.4</TD><TD>16.7</TD></TR>
>>>   </Table>
>>> </PositionList>
>>>
>>
> ---------------------------------------------------------------------- 
> ----
> 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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