GEO Schema Design
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Schema Design Running Notes and References
We're working on three areas:
a) [geo in EN world] Simple examples/recommendations on how to incorporate GeoRSS tags into EN schema (finally), and when should folk use full GML vocab.
b) [geo with EN world] how can/should EN data services play with OGC services, including WFS, WCS, catalog...can we expand EN by "adopting" those protocols and focusing our energy on the semantics/schema of the user communities?
c) [EN world in geo]---how we take some of the EN schema/semantics work and leverage it in non-node (e.g. WFS, WCS, RSS) implementations to broaden the view.
1) Confirm our decision to NOT use "where" construct in standard EN schema, we are just using the GML tags from the GeoRSS profile, not the RSS flavored tags implemented in the GeoRSS application schema.. Anything special about how namespace is referenced?
2) Where multiple simultaneous CRS (coordinate reference systems) are desired, we plan to just develop a standard "alternativeCRSLocation" type tag and use GeoRSS GML tags in there. Any precedent you are aware of for that?
3) We are getting questions about KML 2.2 now that it is OGC standard, what is the argument for/against it vs GeoRSS, just want to confirm.
4) One of the key interactions we are looking at is with WFS: a) from the spec it looks like return of WFS has to be GML b) what we are trying to figure out is how to link rich hierarchical data we have in EN schema with WFS/GML, if we could just return an EN schema (and stylesheet) in WFS that wold be easy, but if return needs to be GML maybe that is harder...can we insert schema? or do we need to use GML featurecollection/attribute constructs? I think the latter? I think this explains the schism between geo and data world.
5) What is a good example of the breakpoint for use of GML vs GeoRSS GML? (besides obvious one of geometry and topology) ---are there any conventions/local guidelines that would be usefully adopted to govern GML implementation?
6) What is up with WCS?
Follow up references from Raj Singh:
- WFS Simple: http://www.ogcnetwork.net/wfssimple
- Canadian work (all posted at http://www.opengeospatial.org/standards/dp/) OGC® Canadian Geospatial Data Infrastructure Summary
- Report OGC® Canadian Geospatial Data Infrastructure WFS and GML Best Practices OGC® Loosely Coupled Synchronization of Geographic Databases in the Canadian Geospatial Data Infrastructure Pilot
- Here's the rough draft of a screencast of geographic names geosynchronization at work: http://www.pvretano.com/ows5/geosync/movie/GeoSync.swf
The following documents are pending, but should be public very soon. Links will be posted when they are available.
- Geo-Synchronization Service draft standard
- Web Feature Service - Simple draft standard
- KML Engineering Report (OWS-5 experiments)
