1. Astrogrid Resource Registry Querying the Registry 1.Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, U.K. 2. University of Leicester, Dept of Physics and Astronomy, University Road, Leicester, LE1 7RH, U.K. 3. Anita Richards, Jodrell Bank Observatory, Dept. of Physics Astronomy, The University of Manchester, Macclesfield, Cheshire SK11 9DL, U.K. 4. Nic Walton, Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge. CB3 0HA, U.K. The Astrogrid registry stores metadata about Astrogrid data archives, data transformation services, and storage services that meet the requirements of an astronomer's query. The registry can be accessed by sending an XML query to the registry web service. The registry web service converts an XML query into an XQL query that is applied to the registry XML file. The registry XML file contains metadata for each data archive, transformation service, and archive service registered with Astrogrid; registry service entries that satisfy the user's query are returned by the web service as an XML formatted query response to the user. The Astrogrid registry will soon be changing to reflect changes to the IVOA’s recommended VOResource v0.8.3 schema as well as implementations of ADQL in addition to XQuery. Metadata The Astrogrid metadata schemas used through Iteration 3 (July 1 – September 30, 2003) are based closely on the IVOA's resource registry recommendations, particularly Dr. Robert Hanisch's "Resource and Service Metadata for the Virtual Observatory: Version 7." There are four basic subsets of metadata: Content metadata can generically describe dataset services, communities, other registries, and MySpace Identity metadata includes the resource's title, a short name, and its identifying URI. Curation metadata includes metadata about the service itself, such as creator, publisher, location, and mirrors. Service metadata concepts include information about service access, standards, and locations. Localising resources in the Virtual Observatory E. Auden 1, T. Linde 2, K. Noddle 2, A. M. S. Richards 3, N. Walton 4 Query UCD Field Data Registry Home Astrogrid Virtual Observatory Registry Interface Query Parser Registry Web Portal: The user queries the registry through a web based GUI. Query Query Parser: The query parser converts the XML query to XQL and sends it to the registry. This class also reformats the XML query response from the registry. Registry Service: The GUI sends the query to the registry web service. The query response is send through the web service back to the GUI. Registry: The registry executes the XQL query against the XML registry file. The query response is sent back to the Query Parser. Example service entry: USNO-B identity metadata Three identity metadata elements: title, shortName, and identifier. <identity xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://www.astrogrid.org/schema/registry_v1_0.xsd"> The USNO-B Catalog USNO-B http://ledas-svc.star.le.ac.uk/blasta/usnobhelp.php Types of Resources The IVOA defines a resource as any virtual observatory element that can be described in terms of a name, a unique identifier, and curation / maintenance metadata. Current list of Astrogrid resource types: Survey Education Outreach epoResource Animation Artwork Background Basic Data Press Organization Project Integrated Name Resolver Community My Space Registry Archive Bibliography Catalogue Journal Library Simulation Historical Photographic Astrogrid Registry web browser Registry Administration GUI The Astrogrid registry browser allows users to query the registry XML file using any element of metadata stored in the registry. Although the GUI implementation only permits two conditions in a query, the registry web service can process any query submitted in XQuery syntax. Although the registry has been developed with an XML file backend queriable by XQuery, future Astrogrid registry work may migrate to a DBMS backend that can be queried with a combination of ADQL and SQL. In addition, the Astrogrid registry schema will evolve to reflect the IVOA’s recommendations for registry metadata in the VOResource version 8 schemas. The current registry can be used by astronomers, web services, and other Astrogrid components, but continued application of IVOA compliance will produce a registry capable of interaction with other grids, as well. Administration of the registry currently relies on a human user editing the XML file by hand or by making changes through a web GUI interface. The Astrogrid registry administration portal allows authorized users to add, edit, and delete existing resource entries. After the user selects a specific registry to administer and applies the changes to a resource entry, these changes are reflected immediately in the registry and can be queried in the browser. Future work to registry administration will enhance the web GUI and provide additional methods of administration. Astrogrid researchers have developed scripts that can harvest resource entries from text emailed by data providers, and the IVOA is currently discussing recommendations for automatic metadata harvesting.