Expressing position in RDF

[Matthew Graham]

Hi,

Hey, not all of us observe Columbus Day!

On Oct 13, 2008, at 7:24 PM, Ed Shaya wrote:

> Matthew Graham wrote:
>> Hi,
>>
>> A practical semantic astronomy question:
>>
>> I want to represent the relationship "object has a RA of 134.556"  
>> as an RDF triple. Is there any existing ontology that would allow  
>> me to do this? The best I've seen so far is to use the UCD as the  
>> predicate.
>>
>>    Cheers,
>>
>>    Matthew
> It is usually not a good idea to put out a question late on Friday  
> afternnoon before a 3 day holiday, if you want a fast response.
>
> Here is "MyStar has a J2000 RA of 34.5343 degrees, it would be  
> something like this in N3:
>
> :MyStar a a:star;
>      ivoa:hasPosition :MyCoordinates.
>
> :MyCoordinates a  
> a:J2000Coordinates 
> ;                                                        
> geo:hasCoordinate :myRA.
>
> :MyRA a a:rightAscension;
>     q:hasFloat 34.5343^^xsd:float;
>     q:hasUnits ui:degree.
>
> The following is extracted from an RDF/XML  generated by  
> Protege4_beta.
>
>    <owl:Class rdf:about="#J2000Coordinates">
>       <rdfs:subClassOf rdf:resource="&a;equatorialCoordinates"/>
>   </owl:Class>
>
>     <!-- http://archive.astro.umd.edu/ont/IVOAO.owl#MyStar -->
>
>   <a:star rdf:about="#MyStar">
>       <ivoao:hasPosition rdf:resource="#MyCoordinates"/>
>   </a:star>
>   <!-- http://archive.astro.umd.edu/ont/IVOAO.owl#MyCoordinates -->
>
>   <J2000Coordinates rdf:about="#MyCoordinates">
>       <geo:hasCoordinate rdf:resource="#MyRA"/>
>   </J2000Coordinates>
>    <!-- http://archive.astro.umd.edu/ont/IVOAO.owl#MyRA -->
>
>   <a:rightAscension rdf:about="#MyRA">
>       <q:hasFloat rdf:datatype="&xsd;float">34.5343</q:hasFloat>
>       <q:hasUnits rdf:resource="&ui;degree"/>
>   </a:rightAscension>
>
> Normally, I would put a hasValue FloatValue between MyRa and hasFloat,
> but it is probably workable this way also.
>
> Why do you ask?

I'm encoding VOEvent data as XHTML/RDFa and wanted to know how to do  
positions.

	Cheers,

	Matthew