[OpenLayers-Dev] Using JSON instead of XML for OGC documents

[Anselm Hook]

It feels like GML/JSON should just be done - for openlayers in particular.

It sounds like a good idea.  For cross-domain access and speed,
portability, clarity, and to free GML of XMLisms, reduce programmer
labour and time.

Or at least barring that to try to exploit library based XML loading
and not try to have javascript based parsers that convert XML graphs
into Javascript Object trees.

But I would be suprised if OGC specs really think of XML as an aspect
of their grammer.  I am basically totally ignorant here but maybe
dealing with SLD require XPATH kinds of operators? (In the sense of
where XPATH helps you quickly search XML graphs in convenient ways and
thus may have become a required aspect of dealing with SLD...)...  I
was reading through the spec and there seemed to be some assumptions
about how one was able to discover how to apply a style to a given
geometry...  It was too deep for me to follow completely on short
notice but it was enough to scare me away from wanting to
participate...

Not to grouse over old ground... but note that RDF has an RDF/XML
profile and RDF/JSON and other profiles.  Many web 2.0 type projects
I've seen lately have switched to JSON; in fact I think XML has been
dropped completely pretty much from my (very limited) point of view...

To be honest, if it is indeed XML bound - then it is another mark of
failure in the GML grammer in my mind.  It feels like (from a naive
perspective granted) that it is a grammer that already fails for being
too deep ( the grammer is too granular requiring significant tree
traversal to extract meaning ) and confusing ( it is unclear what
nodes can own what other nodes ) and frankly incredibly weak ( failing
to express operators like 'switch' 'transform' 'grouping' 'citation of
a geometry via pointer reference' ) idiosyncratic language ( ignoring
the history of earlier work in VR and 3d modelling ) and with weak
namespace support as compared to say RDF.  Also, the GML graphs that
you load have to be post-processed because they are not optimal
mappings to the reality of computing hardware; like if dealing with a
3d vector grammer; you're going to express all your points as clumps
so that you can transform them efficiently with vector processing
hardware (like say the playstation 2 built in dual VPU units).   So
you're going to want to have array offset-indexing into your vector
array to describe polygons... keeping vectors in one place...  where
possible.  This sounds overly pendantic; but most video games throw
around 100k lit textured polygons at 60fps; and most GIS renderers
completely choke on 1k polylines; you can see them stutter.  GML gives
me pause; not reassurance...  I'd be happy for somebody to tell me
that these assertions are incorrect.

 - a


On 11/17/06, Adam Hill <adam.hill at gmail.com> wrote:
> Cameron wrote:
> >* In Web Browsers, XML support is patchy.
>
> I am curious. What browsers don't have basic read/write XML support? Opera?
> Safari?
>
> Or is there some missing features that make it just a PITA?
>
> Adam Hill
>
>
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