[Geojson] FW: Features without geometry

[Andrew Turner]

So, I'm still not clear if/how GeoJSON is used to just 'add'
geographic content to larger/richer JSON content. Can an example be
added for clarity - b/c I will definitely be mixing geographic &
non-geographic content together.

Also - regarding omitting vs. null geometry. KML and RSS/Atom both are
valid without any geometry element. So it seems odd that GeoJSON would
break that mold to require a null-geometry.

On 10/3/07, Stephen Battey <Stephen.Battey at dottedeyes.com> wrote:
> > Would this alleviate the concerns of the original poster, if
> > we said "must have a property 'geometry', which must be a
> > GeoJSON Geometry or null" ?
> Yes, that would certainly help.
> Although semantically a null geometry means 'this feature has no
> geometry' I think I can get away with using it to mean 'geometry not
> specified'. The rationale being: if a client specifically asks not to
> receive any geometry then the client should know to interpret
> "geometry": null  as 'geometry not specified'.
> I think that's a reasonable condition to ask of client applications, and
> it means clients can use a GeoJSON parser to parse the JSON regardless
> of whether they query for geometry or centroids, bounding boxes,
> metadata, etc.
>
>
> >From a purely aesthetic point of view, would it be better to use a
> consistent syntax for empty/null geometry and properties?
> We have empty geometry defined as ..
>         "geometry": null
> .. and empty properties defined as ..
>         "properties": {}
>
> Actually, now that I'm thinking out loud (well, on paper), maybe the
> difference is a positive thing. They are, after all, two different types
> of information.
> Also, using 'null' clearly indicates "an empty geometry" whereas an
> empty object might give the impression there is geometry but the data
> ("type" and "coordinates") was inadvertently omitted when the JSON was
> constructed.
>
> The more I think about it the more I like  "geometry": null
> I think it is a useful addition to the spec.
>
>
> Steve
>
>
> > -----Original Message-----
> > From: geojson-bounces at lists.geojson.org
> > [mailto:geojson-bounces at lists.geojson.org] On Behalf Of
> > Christopher Schmidt
> > Sent: 02 October 2007 21:24
> > To: Sean Gillies
> > Cc: geojson at lists.geojson.org
> > Subject: Re: [Geojson] FW: Features without geometry
> >
> >
> > On Tue, Oct 02, 2007 at 01:45:57PM -0600, Sean Gillies wrote:
> > > Thank you for the correction. I much prefer
> > >
> > >    { "geometry": null }
> > >
> > > over
> > >
> > >    { "geometry": {"type": "Empty", ...} }
> >
> > I can get down with that. My primary concern is that if it
> > looks like a duck, it has the same properties as a duck.
> > Since 'null' doesn't look like a duck, then it doesn't need
> > to have any particular properties.
> >
> > Would this alleviate the concerns of the original poster, if
> > we said "must have a property 'geometry', which must be a
> > GeoJSON Geometry or null" ?
> >
> > Is there anyone against this?
> >
> > http://wiki.geojson.org/index.php?title=GeoJSON_draft_version_
> 4&diff=153&oldid=151
>
> Regards,
> --
> Christopher Schmidt
> MetaCarta
> _______________________________________________
> Geojson mailing list
> Geojson at lists.geojson.org
> http://lists.geojson.org/listinfo.cgi/geojson-geojson.org
>
> Incoming e-mail scanned by Altman Technologies
> Email has been scanned for viruses and spam by Altman Technologies
> _______________________________________________
> Geojson mailing list
> Geojson at lists.geojson.org
> http://lists.geojson.org/listinfo.cgi/geojson-geojson.org
>


-- 
Andrew Turner
ajturner at highearthorbit.com      42.2774N x 83.7611W
http://highearthorbit.com              Ann Arbor, Michigan, USA
Introduction to Neogeography - http://oreilly.com/catalog/neogeography