Re: DAML-Spatial Primitives

From: Pete Haglich (
Date: 03/10/03

  • Next message: Adam Pease: "Re: DAML-Spatial Primitives"
    The "locus" vs "location" was a throwaway ancedote about a particular 
    customer, I didn't mean for people to read too much into it.
    As far as the nature of a city being a point vs being a region, I think 
    it goes a bit deeper than what you suggest and it depends on the 
    granularity of the discourse.  For example, for travel itineraries, 
    cities are often treated as points.  However, there are other cases 
    where the "two dimensional properties" of a city are important.  In our 
    use of spatial ontology we have found it useful to accomodate both 
    viewpoints.  I should note, though, that in our use of DAML we don't 
    have something like a "TerritoryFn" which might map an idealized city 
    point to the territory within the city limits.
    On Monday, Mar 10, 2003, at 12:42 US/Eastern, Adam Pease wrote:
    > Pete,
    >   That sounds like a lexicon issue, rather than an ontology issue.  If 
    > a human user wants to use a particular term, that's an issue for the 
    > interface.  A lot of problems occur when one tries to adjust an 
    > ontology, which must support inference, to conform to a human's 
    > linguistic conventions.  We've found that it's straightforward to keep 
    > the two distinct, and have a lexicon file that maps to terms in an 
    > ontology.  That also makes it easier to use the same ontology for 
    > users who speak different languages, as well as those who use 
    > different lingo.  The issue of vagueness in language is related.  A 
    > city is a region, which may have a centroid point that is represented 
    > on a map.  A user may wish to be vague about that, but that's a 
    > language issue, not an ontology issue.
    > Adam
    > At 11:06 AM 3/10/2003 -0500, Pete Haglich wrote:
    >> We have adopted that in our current spatial ontologies, using the 
    >> term "locus" because "location" had connotations to our customer.  
    >> The notion of "locus" has child subclasses of Point Locus, Linear 
    >> Locus, Area Locus, and Volume Locus.
    >> We find that the blurring of distinction between point and area is 
    >> sometimes useful when discussing things like cities.  For some 
    >> purposes they are usefully modeled as points, in other cases, it is 
    >> more appropriate to reference the associated territory within the 
    >> city limits.
    >> On Friday, Mar 7, 2003, at 14:55 US/Eastern, Austin Tate wrote:
    >>> The idea being that a neutral word like location which does not 
    >>> restrict
    >>> the meaning to be only one of a "point" or "area" or "volume" and 
    >>> leaves
    >>> nature of the "location" open can be useful to allow relationships 
    >>> to be
    >>> stated to give real meaning.
    >> --
    >> Pete Haglich, ISX Corporation
    >> Virginia Beach, VA
    >> Mobile (757) 572-5913
    Pete Haglich, ISX Corporation
    Virginia Beach, VA
    Mobile (757) 572-5913

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