[GeoJSON] Fwd: data series, time series in GeoJSON

[Tom MacWright]

There's a bit of a more recent conversation from last month[1] on the more
general case of 'values along a line', with a similar conclusion - it's not
an easy thing to implement for any general case and it's something that's
possible to do 'by convention' without a change to the standard.

[1]:
http://lists.geojson.org/htdig.cgi/geojson-geojson.org/2013-August/000821.html


On Thu, Sep 19, 2013 at 11:48 AM, Matt McClure <matthewlmcclure at gmail.com>wrote:

> Hi,
>
> I'm reading the GeoJSON spec as I'm working on a way to represent time
> series data. I've looked through the mailing list archives and I've
> found a conversation from October[1] and November 2011[2], and a
> rejected proposal on the wiki.[3]
>
> Does section 3[4] allow arbitrary CRS values, or does the condition
> that "" disqualify all CRSs that would use dimensions other than one
> of the two examples in section 2.1.1.[5]?
>
> I wonder if a time series representation would conform to the existing
> GeoJSON 1.0 spec using an alternative CRS. For example, using URNs as
> described in "Definition identifier URNs in OGC namespace"[6], I might
> construct a compound CRS and use it as follows:
>
>     {
>       "crs": {
>         "type": "name",
>         "properties": {
>           "name":
>
> "urn:ogc:def:crs,dataType:OGC:1.1:time,crs:OGC:1.3:CRS84,verticalDatumType:OGC:1.0:geoidal"
>         }
>       },
>       "type": "LineString",
>       "coordinates": [
>         [<time>, <lat>, <lng>, <alt>], [...], ...,
>       ]
>     }
>
> Would an example like this conform to GeoJSON 1.0?
>
> Best,
> Matt
>
> [1]:
> http://lists.geojson.org/htdig.cgi/geojson-geojson.org/2011-October/000597.html
> [2]:
> http://lists.geojson.org/htdig.cgi/geojson-geojson.org/2011-November/000601.html
> [3]: https://github.com/GeoJSONWG/geojson-spec/wiki/Data-Series-Proposal
> [4]:
> http://www.geojson.org/geojson-spec.html#coordinate-reference-system-objects
> [5]: http://www.geojson.org/geojson-spec.html#positions
> [6]: http://portal.opengeospatial.org/files/?artifact_id=24045
>
>
> --
> Matt McClure
> http://matthewlmcclure.com
> http://www.mapmyfitness.com/profile/matthewlmcclure
> _______________________________________________
> GeoJSON mailing list
> GeoJSON at lists.geojson.org
> http://lists.geojson.org/listinfo.cgi/geojson-geojson.org
>
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