Re: [linking-data] What do the links mean?

2015-09-24 19:37 GMT+02:00 Krzysztof Janowicz <janowicz@ucsb.edu>:

> Hi Frans,
>
> I am not exactly sure what you mean. Are you thinking about conceptual
> neighborhood graphs for spatiotemporal relations?
>
> For the temporal counterpart, there is an excellent paper from 1992 on
> 'Temporal reasoning based on semi-intervals' from Christian Freksa. There
> is of course tons of work on spatial models including research on very
> specific cases.
>
> Combining spatial and temporal relations into a common system would lead
> to a huge amount of relations and  most of them would not be distinguished
> by humans (which was already shown for multiple spatial relations).
>

No, I wasn't thinking about conceptual neighborhood graphs, I did not know
they existed :-)
And perhaps I got carried away...

I thought I could see another application of the idea that it is possible
to make a problem simpler by looking at it from a broader perspective. I
still like the thought of applying that idea to the problems of CRS:
publications of geometry data like to use spherical coordinates (longitude
and latitude), but when it comes to exact definition of those coordinates
we get in to problems. Is WGS84 meant if the CRS is not specified? Should
we encourage WGS84 as a default CRS? Those are though problems, but it
occurred to me that by broadening our scope from geographical to spatial we
could simplify matters. If we want to be able to use non-geographical
spatial data together with geographical spatial data on the web, a common
model for coordinates is needed, and such a common model could be a lot
simpler than currently used CRS models, at a certain level of abstraction.

Similarly I thought that the tricky situation with so many types of
relationships (temporal, distance, one dimensional spatial, two dimensional
spatial, three dimensional spatial) could be simplified by working with
common relationships. But I can imagine it won't be possible to harmonize
temporal and spatial relationships in such a way (although I can't think of
a fundamental difference between events on a time line and events on a
geometric line, as in linear referencing). Perhaps it *is* possible to find
common ground for n-dimensional spatial relationships? Or if it has been
proven that those cases should always be treated separately, that would
also be good to know.

Greetings,
Frans


>
> Best,
> Krzysztof
>
>
>
> On 09/24/2015 02:39 AM, Frans Knibbe wrote:
>
> I don't know if this is the right place to bring this up, but something
> occured to me when I looked at the description of Allen's algebra
> <http://Allen%27s%20interval%20algebra> (used for temporal relations):
> the labels for the relationships have similarities with 2D spatial
> relationships (e.g. the DE-9IM
> <https://en.wikipedia.org/wiki/DE-9IM#Spatial_predicates>). Which perhaps
> is no surprise - isn't Allen's algebra essentialy a way of describing
> events on a line, i.e. a one dimensional space?
>
> At the moment I don't have time for searching for research papers and the
> like, but I wonder if a general model for n-dimensional relationships could
> be used for expressing temporal and spatial relationships. The DE-9IM model
> is for 2D space, but in 1D space (linear referencing) and 3D space there is
> also a need for semantics that describe spatial interaction between
> resources. A single base model could perhaps simplify definition of
> spatiotemporal relationships, lessen the amount of required properties and
> provide extra opportunities for reasoning.
>
> Regards,
> Frans
>
>
>
> 2015-09-24 11:11 GMT+02:00 Ed Parsons <eparsons@google.com>:
>
>> In the spatial domain do we use links to represent spatial relationships
>> of hierarchy (x is constituent part of y) and topology (y is adjacent z) ?
>>
>> ed
>>
>> On Thu, 24 Sep 2015 at 09:33 Jeremy Tandy <jeremy.tandy@gmail.com> wrote:
>>
>>> Email thread for collecting discussion on the question: "What do the
>>> links mean?"
>>>
>>> The related wiki entry for this questions is here [1]
>>>
>>> For instructions about how to engage with this discussion, please see my
>>> previous email [2].
>>>
>>> Many thanks. Jeremy
>>>
>>> [1]:
>>> <https://www.w3.org/2015/spatial/wiki/Linking_Data#What_do_the_links_mean.3F>
>>> https://www.w3.org/2015/spatial/wiki/Linking_Data#What_do_the_links_mean.3F
>>>
>>> [2]:
>>> <https://lists.w3.org/Archives/Public/public-sdw-wg/2015Sep/0044.html>
>>> https://lists.w3.org/Archives/Public/public-sdw-wg/2015Sep/0044.html
>>>
>>>
>> --
>>
>> *Ed Parsons*
>> Geospatial Technologist, Google
>>
>> Google Voice +44 (0)20 7881 4501 <%2B44%20%280%2920%207881%204501>
>> www.edparsons.com @edparsons
>>
>
>
>
> --
> Krzysztof Janowicz
>
> Geography Department, University of California, Santa Barbara
> 4830 Ellison Hall, Santa Barbara, CA 93106-4060
>
> Email: jano@geog.ucsb.edu
> Webpage: http://geog.ucsb.edu/~jano/
> Semantic Web Journal: http://www.semantic-web-journal.net
>
>