[GeoJSON] Future plans for GeoJSON

[Stefan Drees]

Am 01.05.13 22:56, schrieb Sean Gillies:
> Howard, I can't let you take all the blame for GeoJSON's crs. A lot of
> that is my doing. And I think you're right that projection in the
> browser (like http://bl.ocks.org/mbostock/4498292 or
> http://bl.ocks.org/mbostock/4319903) changes the game entirely. All
> projecting geographic servers aren't as necessary as they used to be and
> long/lat ("urn:ogc:def:crs:OGC::CRS84") is increasingly sufficient.
>
> Mike, I'm in favor of a single indentifier string for crs as you have
> above for cases where long/lat just won't do. And I think that use of
> RFC 5165 URNs like "urn:ogc:def:crs:EPSG::3857" make the most sense for
> a GeoJSON I-D. Perhaps a future CRSJSON could address cases not covered
> by OGC or EPSG.
>
> Other than Mike's election maps, what would break if we made crs an
> optional string (defaulting to "urn:ogc:def:crs:OGC::CRS84") instead of
> a JSON object?

as I notice some traction behind the first proposals to loosen the 
coupling between the GeoJSON data and the crs (inside the GeoJSON 
object) I updated the draft geojson-i-d in the repo to reflect my 
current understanding of it and to get an idea how this would look like 
in context.

I also suggest to

a) change the name fromcrs to something else to not break existing 
clients, that might have problems with an optional member, whose value 
changes type from object to string and

b) to set the key of this member to crsURN to reflect the domain 
constraint to URNs (for now assumed to be as defined in RFC 5165.

The RFC 5165 has been added to the list of normative references and the 
definition of URN has been inlcuded in the list of definitions.

Draft (paginated Text):
https://raw.github.com/GeoJSONWG/draft-geojson/master/draft.txt

Changes:
https://raw.github.com/GeoJSONWG/draft-geojson/master/CHANGES.txt

Repo:
https://github.com/GeoJSONWG/draft-geojson

Feedback welcome!

All the best,
Stefan.

>
>
> On Fri, Apr 26, 2013 at 11:42 AM, Michael Geary <mg at mg.to
> <mailto:mg at mg.to>> wrote:
>
>     On Fri, Apr 26, 2013 at 9:27 AM, Howard Butler <hobu.inc at gmail.com
>     <mailto:hobu.inc at gmail.com>> wrote:
>
>         As one of the primary forces behind the CRS stuff, I support the
>         removal of CRS from the GeoJSON specification. Adhoc
>         specification of the coordinate system would then be left to the
>         implementor, and a thousand turdblossoms can bloom.
>
>
>     I'm one of those rare people who use the GeoJSON CRS. I built a
>     bunch of election results maps for Google over the last few years,
>     and to speed up the JavaScript code a bit I used Spherical Mercator
>     coordinates since those convert directly to pixels with a single
>     multiplication. So I use this CRS in my GeoJSON files:
>
>          "crs": {
>              "type": "name",
>              "properties": {
>                  "name": "urn:ogc:def:crs:EPSG::3857"
>              }
>          }
>
>     with coordinates like these:
>
>          "bbox": [ 737758, 4231185, 2061653, 5957068 ]
>
>     I suppose it wouldn't make any real difference whether the crs
>     object is in the standard or not, since I could just continue to use
>     it in any case. Maybe if it weren't in the standard I would feel
>     free to simplify it to:
>
>          "crs": "urn:ogc:def:crs:EPSG::3857"
>
>     instead of all the extra structure it has now.
>
>     So I guess I don't have an opinion one way or the other on removing
>     the CRS from the standard, just wanted to mention that I'm using it.
>
>     -Mike
>
>
>
>
> --
> Sean Gillies
>
>
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