<div dir="ltr"><div class="gmail_extra">Karl,</div><div class="gmail_extra">Personally I think that this is best solved with a core and extensions model. GeoJSON is the core, providing a basic feature and geometry model. TopoJSON and GeoJSON-LD are emerging as extensions and it follows that support for temporal properties should also be one. As Sean suggests, your temporal requirements are pretty advanced - many temporal applications like map stories would be satisfied by a simple(r) model. To me TopoTime looks like a further extension of a basic temporal extension.</div>
<div class="gmail_extra">Regards,<br></div><div class="gmail_extra">Jeff<br><br></div><div class="gmail_quote"><blockquote style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class="gmail_quote">
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Date: Tue, 1 Apr 2014 10:02:00 -0600<br>
From: Sean Gillies <<a href="mailto:sean.gillies@gmail.com" target="_blank">sean.gillies@gmail.com</a>><br>
To: Karl Grossner <<a href="mailto:karlg@stanford.edu" target="_blank">karlg@stanford.edu</a>><br>
Cc: "<a href="mailto:geojson@lists.geojson.org" target="_blank">geojson@lists.geojson.org</a>" <<a href="mailto:geojson@lists.geojson.org" target="_blank">geojson@lists.geojson.org</a>><br>
Subject: Re: [GeoJSON] Time and GeoJSON, redux<br>
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<br>
Dear Karl,<br>
<br>
I worked on a little historical gazetteer project for a while and continue<br>
to be very interested in time. While I'm not in favor of making time part<br>
of the GeoJSON core, I think it would be a cool application for GeoJSON-LD.<br>
<br>
I don't agree that CIDOC-CRM or Topotime white papers are good starting<br>
points for this discussion. Rather, I think the right starting points are:<br>
<br>
1. The frequently asked question "how do I represent time series and/or<br>
GPX data in GeoJSON?"<br>
2. How can we extend GeoJSON so that "story map" applications (such as<br>
<a href="http://storymap.knightlab.com/" target="_blank">http://storymap.knightlab.com/</a>) are simple to develop and so that this kind<br>
of data can benefit from the ecosystem around GeoJSON (Leaflet, GitHub<br>
support, etc.<br>
<br>
Fuzzy dates and historical calender system bugs complicate the latter,<br>
certainly, and I feel that GeoJSON should avoid fuzzy dates as it avoids<br>
fuzzy locations. Also, the choice of a standard temporal reference system<br>
will be interesting.<br>
<br>
<br>
<br>
On Fri, Mar 28, 2014 at 3:13 PM, Karl Grossner <<a href="mailto:karlg@stanford.edu" target="_blank">karlg@stanford.edu</a>> wrote:<br>
<br>
> At least three efforts at developing standard representations of<br>
> explicitly temporal objects have begun and are in an early stage of<br>
> development: Topotime [1], the CRMgeo extension to CIDOC-CRM [2], and the<br>
> nascent PeriodO [3]. All of these view temporal objects as inherently<br>
> spatial and vice-versa. Gazetteer-related projects including Pelagios 3<br>
> [4], which is developing an "index of toponyms attested," will have some<br>
> standardized form of representing attested temporal dimensions of a toponym<br>
> and/or its referrent feature.<br>
><br>
> GeoJSON is an important standard for representing geographic features, but<br>
> the specification does not address temporality explicitly. My view is that<br>
> it should, going forward. At present, temporal attributes of a feature can<br>
> be added as a property, but isn't the temporal extent of a feature co-equal<br>
> as a descriptor with its spatial extent? Software can be written (and is)<br>
> to parse values from ad hoc "properties" : { ... }, but will it be useful<br>
> to elevate temporal description to the level of "geometry" in the standard?<br>
><br>
> As a co-developer of Topotime, engaged in collaborative discussions with<br>
> some of the other projects mentioned here, I'd like to start a discussion<br>
> here of how such spatial-temporal representations can or should relate to<br>
> GeoJSON, and the emerging GeoJSON-LD. I've written a few further thoughts<br>
> about it on a blog post [5].<br>
><br>
> Thoughts?<br>
><br>
> [1] <a href="http://dh.stanford.edu/topotime" target="_blank">http://dh.stanford.edu/topotime</a><br>
> [2] <a href="http://www.cidoc-crm.org/docs/Technical%20Report435-CRMgeo.pdf" target="_blank">http://www.cidoc-crm.org/docs/Technical%20Report435-CRMgeo.pdf</a><br>
> [3] <a href="http://caa2014.sciencesconf.org/browse/author?authorid=233410" target="_blank">http://caa2014.sciencesconf.org/browse/author?authorid=233410</a><br>
> [4] <a href="http://pelagios-project.blogspot.com/" target="_blank">http://pelagios-project.blogspot.com/</a><br>
> [5]<br>
> <a href="http://kgeographer.com/wp/joining-space-and-time-in-geographic-features/" target="_blank">http://kgeographer.com/wp/joining-space-and-time-in-geographic-features/</a><br>
><br>
> +++++<br>
> Karl Grossner<br>
> <a href="mailto:karlg@stanford.edu" target="_blank">karlg@stanford.edu</a><br>
><br>
><br>
><br>
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><br>
><br>
<br>
<br>
--<br>
Sean Gillies<br>
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End of GeoJSON Digest, Vol 64, Issue 1<br>
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</blockquote></div><div class="gmail_extra"><br><br clear="all"><br>-- <br>Jeff Yutzler<br>Image Matters LLC<br>Mobile: <a href="tel:%28703%29%20981-8753" value="+17039818753" target="_blank">(703) 981-8753</a><br>Office: <a href="tel:%28703%29%20428-6731" value="+17034286731" target="_blank">(703) 428-6731</a><br>
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