Re: space and time

On 2014-05-29 18:09, Karl Grossner wrote:
> Frans,
>
> My answer to this is: because space and time are not independent of 
> each other - they are aspects of location, maybe better termed "setting."
I think this is the core of the matter: Are space and time truly 
dependent on each other? Or do they just happen to occur together very 
often? If the latter is the case, I think it is better to keep the 
semantics separate. It is one of the things I like about the semantic 
web: vocabularies are modules that  can be mixed and matched at will. 
And if a  vocabulary is designed well it will be as simple as possible 
and not try to model anything outside its scope.

> A very large proportion of data on natural phenomena come to us as 
> {x,y,z,t} and time has been split out previously because it is 
> challenging to keep them together, and a lot of good work can be done 
> with a "snapshot" view.
Isn't this because with methods less advanced than Linked Data it is 
harder to keep related thing together? In Linked Data, would say it is 
not necessary to use a single vocabulary if there is a need to group 
some facts tightly together.

> GeoJSON models geographic features; it is increasingly recognized that 
> events (and periods and processes) are dynamic geographic features. So 
> I would say "when" was an important omission from GeoJSON. If there 
> were a TimeJSON (and Topotime is aimed at that), "where" will be 
> similarly important. I think of them as perspectives on the same thing(s).

OK, I can imagine that time was an omission in GeoJSON. But as far as I 
know GeoJSON is not at liberty to use semantics from other sources. It 
needs to model the world on its own. But in Linked Data it is possible 
to keep things modular and let each group of domain experts work on the 
semantics of their own domain of expertise.

I see some similarities with the set of OGC standards. It started simple 
enough: a standard data type for geometry was needed. But then more and 
more things gravitated towards the model and now the OGC feature model 
encompasses a great many things. A lot of those things are firmly out of 
scope. Now the problem with that model is that it is very large and 
complex and therefore very hard to use, especially for people with only 
a casual interest in geography.

>
> Karl
>
>
> > An interesting observation. I tried to read this discussion 
> <https://github.com/geojson/geojson-ld/issues/9> and - not being that 
> familiar with GeoJSON -
> > wondered why the community apparently has not chosen to  hand over 
> the problem of specification of
> > time to TimeJSON. Is it because TimeJSON does not exist?


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Frans Knibbe
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