W3C home > Mailing lists > Public > www-rdf-calendar@w3.org > April 2004

Re: places and lists of coordinates [was: priority bug, to libby and dan]

From: Masahide Kanzaki <post@kanzaki.com>
Date: Fri, 9 Apr 2004 00:40:38 +0900
Message-Id: <p04320408bc9b1cda632a@[[]]>
To: Dan Connolly <connolly@w3.org>
Cc: www-rdf-calendar@w3.org

At 10:07 AM -0500 04.4.8, Dan Connolly wrote:
>no... its range is: list of float:
>	    <rdfs:range>
>	      <!-- We could express the semantics of this class ala:
>	        :FloatList subClassOf rdf:List,
>	          [owl:onProperty rdf:first; owl:allValuesFrom :FloatLit ],
>	          [owl:onProperty rdf:rest; owl:allValuesFrom :FloatList ].
>		  I think "list of X" is discussed in the OWL specs
>		  somewhere.
>	      -->
>	      <owl:Class rdf:about="#List_of_Float"/>
>	    </rdfs:range>
>  -- http://www.w3.org/2002/12/cal/webize2445.xsl

This seems just defining syntax using OWL, not providing any useful
semantic information for ical:geo. Why not leaving the range undefined, and
let rdf:List things be syntactic convention (or recommendation or whatever)
for strict round trip ?

I think the essential semantics of ical:geo is 'global position' as in RFC
2445, not the value type (list of floats). In this sense, I think we should
be able to use ical:geo to describe a position with any appropriate

>>  <ical:geo rdf:parseType="Resource">
>>   <geo:lat>35.678</geo:lat>
>>   <geo:long>139.770</geo:long>
>>  </ical:geo>
>Hmm... that would be saying there's a list of foats at 35,139 on
>the globe. I don't think that's wise.

No, this is saying there is a position described by WGS84 coordinate system.

>> If, on the other hand, want to describe a place with WGS84, we can use
>> geo:lat/geo:long here (this might not be safely converted back to
>> iCalendar, because there is no way to specify datum).
>> It looks happy solution for both sides. Isn't it ?
>You can relate the list of floats to the place on the globe, but
>I don't think it's a good idea to equate them.

So, I think it's not good idea to define ical:geo as the list of floats.

Remember, we also want to use RDFical vocabulary with other vocab, such as
RSS, FOAF or even XHTML. Strict round trip .ics <-> RDFical is only
relevant when RDFical is generated from iCalendar, and doesn't make much
sense when the vocab is used in, say, FOAF file.

Wouldn't it be enough to say something like 'when converted from .ics,
ical:geo should be expressed as the list of floats so that strict round
trip is possible' ?
Received on Thursday, 8 April 2004 11:40:43 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:14:12 UTC