[OSGeodata] Re: [Geotools-devel] On the catalog tutorial

[Jo Walsh]

dear Stefan, all, 
On Mon, Sep 25, 2006 at 01:52:27PM +0200, Stefan F. Keller wrote:
> >GeoSpatial information. All other associations are handled "implicitly"
> >when working with a reference to a geospatial resource.
> Consider also the fact that geodata can exist without data access services
> but data access services can't. 
http://wiki.osgeo.org/index.php/Geodata_Metadata_Model is where I am
restarting at based on our talks, Stefan, and on the current simple
OSGeo schema that is storing info about geospatial resources. 

Recall this started as "producer view" not a "consumer view" though I
would like both to tend towards being the same. So it deals with data
sets not with individual feature level metadata. As for services it is
just saying "here is a thing at a URI (could be a local file:/// URI), 
there is a loose way ('format') of indicating how best to point any indexer 
at that URI and learn useful spatial things". A service here is just
one potential data source of a data set. One thing this absolutely
does not take into account is presentation data, SLD etc etc. 

Next step for me is to scribble over this model the mappings out to
Dublin Core/GeoRSS/SIOC and to FGDC then to re-sync this with the sql
schema and the object interface to it, then there can be some sample
output and/or i can look harder at just plugging this into GeoNetwork.

I wish I'd had time this week to get more involved with this
discussion - I have just been unable to get off the circuit and it
will be this way for a few more days. Stefan i have not been
commenting on your model proposal because essentially I agree with it. 
I know I am completely glossing over the service discovery service
discovery service half of the problem, I am hoping that someone with a
deeper understanding than my own will contrib a 'eureka' moment :)

> * What's easier for webcrawlers: find data sets (or metadata about it) or
> services?
> * What do data providers more likely do (if they do): register data sets or
> metadata about it containing some data access services or services
> (containing many views to data sets)?
> * And finally: What is easier to describe in a minimal metadata model: data
> sets or data access services?

These are great questions and perhaps we could have them embroidered on
a chintzy plaque to be hung on the wall at the next OWS-4 meeting. 

thanks, 


jo