[wfs-dev] summary of changes from wfs 1.0 to 1.1?

[Steven Keens]

OWS-4 has had a related discussion in the GPW thread.  It deals with
what is formerly known as the Data Aggregation Service (DAS) and
currently known as the GML Feature Fusion Service (FFS).

You can read the related page at:

https://portal.opengeospatial.org/wiki/twiki/bin/view/OWS4/GMLFeatureFus
ionService

The page originally started as documentation of the DAS/FFS interface
but moved on to dealing with joining features and discusses some of the
issues.

Cheers,
--
Steven Keens
PCI Geomatics Committed to Image-Centric Excellence


> -----Original Message-----
> From: wfs-dev-bounces+keens=pcigeomatics.com at opengeospatial.org
> [mailto:wfs-dev-bounces+keens=pcigeomatics.com at opengeospatial.org] On
> Behalf Of Panagiotis (Peter) A. Vretanos
> Sent: Monday, October 16, 2006 4:39 PM
> To: John Herring
> Cc: 'Chris Holmes'; geoserver-devel at lists.sourceforge.net; wfs-
> dev at opengeospatial.org; 'Ian Turton'
> Subject: Re: [wfs-dev] summary of changes from wfs 1.0 to 1.1?
> 
> John Herring wrote:
> > Peter,
> > 	Better yet, what is the OGC document number of the
> > change request that removed join?  That should explain it.
> >
> > Regards,
> > John
> >
> 
> As far as I know there was no formal change proposal.  Clemens raised
> the issue of dynmaically encoding joins through the WFS interface and
> after discussion within the RWG, it was put to a vote and everyone
> present decided to remove joins.
> 
> Please note that I am not the RWG chair.  I am simply reporting what
> happened.
> 
> >
> > Peter,
> > 	Could you be more specific about why you are
> > thinking of dropping joins.
> >
> 
> Because it is unclear how two joined features would be composed in GML
> to generate a response and what the GML schema would even look like.
> 
> > 	A query without a join could not even do basic
> > spatial query, so how is join-less WFS to do anything of
> > value spatially other than some sort of "get features (with
> > some attribute and type restrictions) within this (constant)
> > widow?" Without a join, one of two spatial parameters of a
> > spatial operation will have to be a constant.
> >
> 
> Even though joins cannot be encoded in the WFS interface this does not
> mean that you cannot support joins (spatial or otherwise).  It simply
> means that you must create a view of the joined features (and a GML
> schema to encode it XML) and offer that view through the WFS.
> 
> I other words you cannot "dynamically" request that a WFS join two
> features; the join must be pre-specified in a GML application schema
and
> that schema can be offered through the WFS.
> 
> > 	That is "mostly useless" as query. That cannot be
> > what you mean.
> >
> 
> I wouldn't say "mostly useless".  Most other OGC services (WMS, WCS,
> etc.) only support the type of query that you describe and they do
> useful work.  Don't they? :)
> 
> Ciao.
> 
> --
> Panagiotis (Peter) A. Vretanos          CubeWerx Inc.
> Big Kahuna (Senior Database Developer)  http://www.cubewerx.com
> Tel. 416-701-1985 Fax. 416-701-9870     pvretano at cubewerx.com
> 
> "If you want to make an apple pie from scratch, you must first
>   create the universe." -- Carl Sagan
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