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Re: Request for comments on GeoJSON-LD vocab and context

From: Sean Gillies <sean.gillies@gmail.com>
Date: Tue, 3 Jan 2017 08:44:31 +0100
Message-ID: <CAOodmJoWsJnw-yPFT6=OpxMzGwsO9YxieUCjmZoo5YbAd7Anmg@mail.gmail.com>
To: Gregg Kellogg <gregg@greggkellogg.net>
Cc: public-linked-json@w3.org
Thanks, Gregg. I've fixed the syntax and pushed a new tagged revision to
http://geojson.org/geojson-ld/. I'll revise again with respect to
coordinate arrays after JSON-LD 1.1 is published.

Yours,

On Mon, Jan 2, 2017 at 8:53 PM, Gregg Kellogg <gregg@greggkellogg.net>
wrote:

> Hi Sean, some minor points:
>
> The context is missing a comma at the end of line 18, and has an extra
> comma at the end of line 19. It should be the following:
>
>     "coordinates": {
>       "@container": "@list”,
>       "@id": "geojson:coordinates"
>     }
>
> Otherwise, it looks fine.
>
> Using that context, instead of the example you show, gives somewhat
> different output, as coordinates are in list form, which at least allows
> you to preserve the order of the coordinates.
>
> Note that there is an open feature request specifically designed for
> supporting the GeoJSON coordinate system [1]. Basically, this would allow
> you to define value mappings for an array within a context definition:
>
> {
>   "@context": {
>      "coordinates": {
>         "@id": "geojson:coordinates",
>         "@container" : "@list",
>         "@values" : {
>            "@type" : "geojson:Coordinate",
>            "@container" : "@set",
>            "@values" : [
>                {"@type" : "xsd:double", "@id":"geo:longitude"},
>                {"@type" : "xsd:double", "@id":"geo:latitude"}
>            ]
>         }
>      }
>   },
>   "@graph" : [{
>    "@id" : "ex:LineString1",
>     "coordinates" : [
>           [
>             3.1057405471801753,
>             51.064216229943476
>           ],
>           [
>             3.1056976318359375,
>             51.063434090307574
>           ]
>     ]
>   }]
> }
>
> The idea is that each element of the array would be assigned a particular
> @type (datatype, or @id) and @id (property URI). In this case, the rendered
> RDF might look something like the following:
>
> @prefix geojson: <...> .
> @prefix ex: <http://example/> .
> @prefix xsd: <...> .
> ex:LineString1 geojson:coordinates ([
>   a geojson:Coordinate ;
>   geo:longitude “3.1057405471801753”^^xsd:double ;
>   geo:latitude “51.064216229943476”^^xsd:double ;
> ], [
>   a geojson:Coordinate ;
>   geo:longitude “3.1056976318359375”^^xsd:double ;
>   geo:latitude “51.063434090307574”^^xsd:double ;
> ]) .
>
> Another proposal would introduce a JSON datatype to hold JSON values in an
> RDF LItera [2]l:
>
> This might look something like the following:
>
>     {
>       "@context": {
>          "coordinates": {
>             "@id": "geojson:coordinates",
>             "@container" : "@list",
>             "@type": "@json"
>          }
>       },
>       "@graph" : [{
>        "@id" : "ex:LineString1",
>         "coordinates" : [
>               [
>                 3.1057405471801753,
>                 51.064216229943476
>               ],
>               [
>                 3.1056976318359375,
>                 51.063434090307574
>               ]
>         ]
>       }]
>     }
>
> That could render something like the following:
>
> @prefix geojson: <...> .
> @prefix ex: <http://example/> .
> @prefix xsd: <...> .
> ex:LineString1 geojson:coordinates (
>   “[3.1057405471801753,51.064216229943476]”^^jsonld:JSON,
>   “[3.1056976318359375,51.063434090307574]”^^jsonld:JSON
> ) .
>
> The former gives better RDF results, but the later is probably more
> generically useful.
>
> Feedback from the GeoJSON community would be really useful in helping to
> set priorities for JSON-LD 1.1.
>
> Gregg Kellogg
> gregg@greggkellogg.net
>
> [1] https://github.com/json-ld/json-ld.org/issues/397
> [2] https://github.com/json-ld/json-ld.org/issues/333
>
> On Jan 2, 2017, at 4:27 AM, Sean Gillies <sean.gillies@gmail.com> wrote:
>
> Dear all,
>
> I've published an RDF vocab, JSON-LD context, HTML documentation, and
> PURLs for GeoJSON elements to assist those that want to process GeoJSON
> data in a JSON-LD context. I'd be grateful if anyone can point out
> unacknowledged gaps or suggest improvements in the RDF, context, or text.
>
> http://geojson.org/geojson-ld/
>
> Thanks in advance, and best wishes for the new year!
>
> --
> Sean Gillies
>
>
>


-- 
Sean Gillies
Received on Tuesday, 3 January 2017 07:45:04 UTC

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