[OSGeo-Discuss] I just saw this link go by my email ....

[Randy George]

Hi,

	Thanks for the link. I am glad to see that GOS NSDI etc are fairly
far along in the discovery services angle.

	Also interesting, for anyone looking into the potential of catalogue
services: http://csi.cgiar.org/geonetwork/documents/fgdc_presentation.pdf

After skimming the OGC CSW 2.0.1 and trying a few experiments on CSW call
chains looking for WMS services at
http://www.geodata.gov/aimscsw/csw2.0?service=CSW&version=2.0.0&request=getc
apabilities, I didn't find an easy way to search for WMS/WFS/WCS services
(using GetRecords), but I am a newbie on CSW. I did find some more
interesting SOAP services! 

Perhaps http://wiki.osgeo.org/index.php/Geodata_Discovery_Working_Group
http://wiki.osgeo.org/index.php/Geodata_Metadata_Requirements
is working out an approach to the discovery issue from osgeo perspective.

Discovery service is a need and a lot more complex than I had thought at
first glance. Just a way to find getCapabilities links on available OWS
services is a good start. FGDC metadata is certainly complete and CSW is
flexible, but in the meantime lightweight metadata would work. 

I like this note:
Per Chris Holmes': "Something much more lightweight, that other services can
crawl."

On a separate note:
	I have sometimes been frustrated by the imposition of a front end
client to services, hiding the middle tier OWS from direct access. Quite a
few services seem to have ESRI clients in the front and require some time
consuming investigation to get at the getCapabilities url. 
	"Open", I think, should entail open to other service chains and
client interfaces, and a good start would be some neutral url repository.
Detailed metadata like owner, bbox, attributes... are available from that
basic starting url, at least on OWS. 

Thanks
Randy

-----Original Message-----
From: Doug Nebert [mailto:ddnebert at fgdc.gov] 
Sent: Monday, July 31, 2006 11:40 AM
To: discuss at mail.osgeo.org
Subject: Re: [OSGeo-Discuss] I just saw this link go by my email ....

Randy George wrote:
> Hi Paul,
> 
> 	Very helpful overview.
> 
> I didn't know - "GeoServer includes support for the Z39.50 catalog server"

> 
> There aren't very many OWS catalogue services around. 
> Although, this is a useful alternative:
> http://www.refractions.net/white_papers/ogcsurvey/index.php :) 
> 
> Actually bare links to capabilities xml might be just as useful as a full
> blown OGC Catalogue. 
> 
> Seems like an OGC Catalogue service (or something like it) would be a
useful
> service for OSGeo to host, since public OWSs hold a lot of promise for the
> data side of open source. 
> 

There are three protocols for OGC Catalogue Services: Z39.50 (400+ 
registered servers), HTTP CS-W web interface (at least 50 instances), 
and CORBA (perhaps 10).

> I would think NSDI(http://www.fgdc.gov/grants )would want to implement at
> least a catalogue service for USA agencies (part of One Stop). OSGeo is a
> 'bit' more internationally oriented and could better perform the role of
> international OWS cataloguing. A combination of search and community
> populated OGC services would really help. Right now it's difficult to find
> url's to services, many are still experimental, some are not publicized
due
> to resource limitations.
> 

The geodata.gov service does expose both a CS-W and Z39.50 interface to 
search all its resources (services and data) with the response returned 
as XML ("Full" form as FGDC XML).

Z39.50 entrypoint: z3950s://gos2.geodata.gov:210 (databasename=default)
CSW: 
http://www.geodata.gov/aimscsw/csw2.0?service=CSW&request=getcapabilities

> Hmm, I just ran across this:
> http://wiki.osgeo.org/index.php/Geodata_Discovery_Working_Group
> Looks like work in progress. Has anyone looked into a 2007 grant proposal
to
> NSDI?
> 
> thanks
> Randy

-- 

Douglas D. Nebert
Geospatial Data Clearinghouse Coordinator, Information Architect
FGDC/GSDI Secretariat   Phone: +1 703 648 4151  Fax: +1 703 648-5755

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