[GeoJSON] Time and GeoJSON, redux

[Karl Grossner]

At least three efforts at developing standard representations of explicitly temporal objects have begun and are in an early stage of development: Topotime [1], the CRMgeo extension to CIDOC-CRM [2], and the nascent PeriodO [3]. All of these view temporal objects as inherently spatial and vice-versa. Gazetteer-related projects including Pelagios 3 [4], which is developing an "index of toponyms attested," will have some standardized form of representing attested temporal dimensions of a toponym and/or its referrent feature. 

GeoJSON is an important standard for representing geographic features, but the specification does not address temporality explicitly. My view is that it should, going forward. At present, temporal attributes of a feature can be added as a property, but isn't the temporal extent of a feature co-equal as a descriptor with its spatial extent? Software can be written (and is) to parse values from ad hoc "properties" : { ... }, but will it be useful to elevate temporal description to the level of "geometry" in the standard? 

As a co-developer of Topotime, engaged in collaborative discussions with some of the other projects mentioned here, I'd like to start a discussion here of how such spatial-temporal representations can or should relate to GeoJSON, and the emerging GeoJSON-LD. I've written a few further thoughts about it on a blog post [5]. 

Thoughts? 

[1] http://dh.stanford.edu/topotime 
[2] http://www.cidoc-crm.org/docs/Technical%20Report435-CRMgeo.pdf 
[3] http://caa2014.sciencesconf.org/browse/author?authorid=233410 
[4] http://pelagios-project.blogspot.com/ 
[5] http://kgeographer.com/wp/joining-space-and-time-in-geographic-features/ 

+++++ 
Karl Grossner 
karlg at stanford.edu 


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