- From: Norman Gray <norman@astro.gla.ac.uk>
- Date: Tue, 9 Dec 2008 11:51:24 +0000
- To: Toby A Inkster <tai@g5n.co.uk>
- Cc: John Graybeal <graybeal@mbari.org>, Semantic Web <semantic-web@w3.org>
Toby, hello. On 2008 Dec 9, at 07:39, Toby A Inkster wrote: >> It would appear the people working on SWEET have thought about it: >> http://sweet.jpl.nasa.gov/2.0/spaceCoordinates.owl >> I particularly notice Cartesian is pretty similar to what you've >> suggested. > > > That looks exactly like what I'm after - thanks. A potential problem is that SWEET is potentially a bit too upper-level for what it sounds like you want. In particular #Cartesian doesn't appear to refer to a reference system. Also, unless you're talking about a projection (ie, a map), you want a non-cartesian coordinate system for the lunar surface, rather than a plane. A possible alternative is STC <http://www.ivoa.net/Documents/latest/STC.html >. This has a _lot_ more detail than SWEET, and is expressly designed as a solution to the problem you describe, but there is not as yet a great deal of software support for it. (Also, STC is defined as an XSchema -- if you're interested, I could roll you an RDFS version of it). FITS has world-coordinate system support, with lots of software support, and pulling that into the ontological world is one of my 'real soon now' projects. Given that you want something more informal, it sounds like the most appropriate thing would be just: @base <urn:example#>. @prefix coord: <http://sweet.jpl.nasa.gov/2.0/spaceCoordinates.owl#>. <#MyLunarCoordinates> a rdfs:Class; rdfs:subClassOf coord:Geographic; rdf:comment "Coordinates with respect to <http://adsabs.harvard.edu/abs/2002cosp...34E1305W >". ...which gives coord:Longitude, coord:Latitude, coord:Vertical. Note that there are multiple lunar coordinate systems, as that abstract notes. I'm not sure, off the top of my head, how to identify the current IAU-endorsed one (if there is one), or indeed how to find the definition of the coordinate system referred to in that abstract (which may have been a kite being flown). There's a mention of lunar geodesy in [1], but this is starting to get fiddly all over again... All the best, Norman [1] http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/10527/1/02-2551.pdf -- Norman Gray : http://nxg.me.uk Dept Physics and Astronomy, University of Leicester
Received on Tuesday, 9 December 2008 11:52:02 UTC