[OSGeodata] discovery requirements (some thoughts)

[Jody Garnett]

Thanks Tom, if if the spot is not already covered I would love to 
represent a client programmer :-)
Jody
> I think some sort of face-to-face would be really helpful.  Perhaps we
> can have small presentations from:
>
> Approaches:
>  - Tom (owscat)
>  - Stefan (OAI approach)
>  - Paul Ramsey (Google scraping)
> Software:
>  - Jeroen (GeoNetwork)
>  - someone from deegree?
>
> - discussion of pros and cons of approaches
> - timelines
> - way forward
>
> Comments?
>
> ..Tom
>
>  
>
>
> ________________________________
>
> 	From: Stefan F. Keller [mailto:sfkeller at gmail.com] 
> 	Sent: 22 August, 2006 8:23 PM
> 	To: geodata at geodata.osgeo.org
> 	Subject: [OSGeodata] discovery requirements (some thoughts)
> 	
> 	
> 	I just wanted to ask if we still agree in defining an exchange
> model and a protocol which of course should be in sync with the metadata
> model for geodata?
> 	
> 	BTW: A preliminary program of FOSS4GIS is out. Any news about a
> BOF session? 
> 	
> 	Here are some additional thoughts:
> 	* Users need search services to discover geographic information.
> 	* Geodata owners need a metadata management tool (which implies
> an internal metadata model).
> 	* Geodata owners and service providers need (i) a metadata
> exchange model, (ii) an encoding of it, as well as (iii) a protocol for
> the exchange, dissemination and sharing of metadata. 
> 	* Metadata should be strictly free (LGPL?).
> 	
> 	A preliminary scenario:
> 	* Users search or browse through metadata records. They use a
> web app. or a search component out of a desktop GIS (remark: Users don't
> search services per se). 
> 	* 'Search service providers' enable the discovery of geodata and
> 'filter services', like transformation services (Note: WMS is a 'data
> access service' and belongs to geodata not to filter services)
> 	* 'Search service providers' gather (harvest) their information
> from 'data/filter service providers' and need a protocol to do this. 
> 	* 'Data/filter service providers' offer metadata over this
> protocol. They typically also implement 'data access services' (WMS,
> WFS) or they offer 'filter services'.
> 	
> 	Building blocks needed:
> 	1. A geometadata management model ( e.g. internal to
> telascience)
> 	2. Tools to manage the geometadata
> 	3. A geometadata exchange model
> 	4. An encoding of the geometadata exchange model (probably XML)
> 	5. Geometadata exchange protocols
> 	
> 	What I am especially interested in is 3 to 5. For the protocols
> I see two specifications, both already implemented and ready to go
> (given 2. and 3. are determined!): 
> 	A. Simply publish XML files of geometadata (exchange model) on
> the web (=HTTP with autodiscovery).
> 	B. OAI-PMH which uses geometadata exchange model as its
> specialized metadata model type (data providers needed to register but
> search services can do better focussed crawling). 
> 	
> 	There are some exciting ideas around like embedding hints into
> the geometadata exchange model or THUMP from IETF which lead to
> something between A. and B.
> 	
> 	-- Stefan 
>
>
>