Geodata Committee Eighth Meeting
Chair: Jo Walsh IRC: #osgeo channel on irc.freenode.org Date: 2006-August-30 (at least in the Americas and Europe) Time: (fixed time)
- Discussion of Simple Catalog Interface idea that has been circulating on the mailing list
- How are implementations going?
- What kind of prior art (UDig,etc?) should really be taken into account
- Picking a better namespace for Geodata Metadata Requirements
- What's missing from the latter in the light of [] Stefan's thoughts about metadata properties useful in Dublin Core
- Possibility of BOF/session at FOSS4G
- Update and comments on the status of the Geodata Repository
In attendance - Jo Walsh, Norman Barker, Chris Schmidt, Schuyler Erle, Markus Neteler, David Bitner, Norm Vine, the regular IRC peanut gallery
This meeting revolves around discussion of the Simple Catalog Interface idea that's been on the lists for a while. Stefan Keller (who couldn't make the meeting) has been summarising his thoughts starting here: http://www.geometa.info/rappiinfo/wiki/index.php/OSGeodata particularly in regards to an OAI-PMH compliant interface for geodata metadata exchange.
Chris jumps in to show off a quick prototype of an OpenLayers interface on top of a store of WMS services and what's advertised in their GetCapabilities. http://world.freemap.in/metadata/maplayer.html - this is with the as-yet-unreleased OpenLayers 2.0 with box drawing support among many other things, with GetCapabilities collected from the Google Search API.
Underneath it is a small webservice powered by Sean Gillies' OWSLib - also in heavy redevelopment - which emits JSON objects which correspond to some part of the capabilities - extents and so on. Underneath that is the database that Jo's been working on to store the Geodata Metadata Requirements worked out over previous geodata meetings for OSGeo's Geodata Repository project.
Jo's been working with some of Stefan's ideas - a very simple OAI-PMH interface for transferring geometadata around in RDF. It sort of works, but needs more metadata underneath to really show its face.
Norman is focused on development of a lightweight discovery mechanism - "a bit like a service registry, but we do all the finding"; something that can feed into a distributed caching effort. The goal state is a server that allows JPIP streaming from multiple data ( service ) resources. He's building a J2EE service that re-uses the OSGeo geometa schema.
Jo talks about the background of the OSGeo effort - how a metadata store connects to the early-days Geodata Discovery Working Group and how this can lead into dynamic repackaging of data. Schuyler notes that these are basically two different problems with the same underlying solution - a simplest-useful-thing metadata store with one or more commonly understood RESTful interfaces.
"nhv is intrigued by the possibility of the process of getting data avail for a service might just be the process whereby the metadata is formalized" - this should work just as well for data one is publishing as data one is discovering. It's in the same kind of space as mapdex, but with uses for data providers as much as data aggregators.
There basically is no decision or agreement on what the RESTful interface should look like - in a way it doesn't matter as long as we can agree on it - or what it transfers as long as people can easily reuse it - and this is the easiest part of the problem - the core is getting the model right, and hopefully Geodata Metadata Requirements is a long way towards that. Jo and Norm will continue to work on their implementations and socialise them on the geodata mailing list. We'll hopefully have a BOF or breakout session on the subject at FOSS4G.