VODA A Sampo Project Johan Lindroos CSC Scientific

Introduction and Motivation Ø Sampo is a collaborative project between Finland ESO to investigate

High-Level Architecture AR Plastic enabled apps. VODA – GUI, DB, Application interfaces. Local data

Virtual Directory? Ø A local, persistent, private “view” of the VO Ø Storing references

Data discovery - in a general way. . . Ø VODA uses the Astrogrid

Downloading data Ø References in the Virtual Directory can be downloaded to a local

Why the Astrogrid AR? Ø The Astrogrid Astro Runtime (AR) allows simple access to

Experiences with VO-standards Ø IVOA standards allow the construction of a very general tool

Why Plastic? Experiences. . . Ø Plastic is EASY and QUICK - only a

Conclusions Ø VODA is a simple experimental implementation of the Virtual Directory concept Ø

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VODA - A Sampo Project Johan Lindroos – CSC Scientific Computing Ltd, Finland Pekka Järveläinen – CSC Scientific Computing Ltd, Finland Richard Hook - ESO, Garching, Germany http: //www. eso. org/sampo lindroos@csc. fi VODA - IVOA Victoria 17 May 2006

Introduction and Motivation Ø Sampo is a collaborative project between Finland ESO to investigate future data processing requirements and technologies and perform pilot studies Ø A small part of Sampo has been looking at the VO, and specifically the relationship between remote VO resources and local data analysis applications Ø VODA is an experiment to establish a personal, persistent local “virtual directory” of VO data resources and link this with visualization tools and the VO itself using the Astro Runtime (AR) and Plastic VODA - IVOA Victoria 17 May 2006

High-Level Architecture AR Plastic enabled apps. VODA – GUI, DB, Application interfaces. Local data VODA - IVOA Victoria 17 May 2006 XML-RPC enabled apps.

Virtual Directory? Ø A local, persistent, private “view” of the VO Ø Storing references to remote and local data and metadata Ø User may organize these references Ø Visualize (Aladin/TOPCAT/DS 9 etc. ) Ø User may add new resources to his “library” from new queries or from external sources Ø An application interface is on the way VODA - IVOA Victoria 17 May 2006

Data discovery - in a general way. . . Ø VODA uses the Astrogrid Astro Runtime (AR) for access to VO resources through standard IVOA protocols (Registry, SIAP, SSAP, Cone etc. ) Ø Results can be stored in the Virtual Directory, visualized directly by local tools, downloaded, or passed to Plastic-aware applications Ø The Virtual Directory can be updated with search results from any search tool that is Plastic-aware VODA - IVOA Victoria 17 May 2006

Downloading data Ø References in the Virtual Directory can be downloaded to a local disk when required Ø In future, a download directly into VOSpace could be possible Ø Download isn’t needed for browsing metadata Ø Handles download for tools which demand local data (eg, DS 9) VODA - IVOA Victoria 17 May 2006

Why the Astrogrid AR? Ø The Astrogrid Astro Runtime (AR) allows simple access to the Astrogrid Registry and to application and dataservices (SIAP, Cone Search etc) Ø AR also offers the possibility of future access to My. Space/VOSpace Ø Use of AR hides future changes of IVOA standards from VODA itself Ø Using the AR is much easier than re-implementing all its facilities from scratch! VODA - IVOA Victoria 17 May 2006

Experiences with VO-standards Ø IVOA standards allow the construction of a very general tool which makes few assumptions about the data products - as intended! Ø Some problems were encountered when services do not support the specifications fully (eg, some SIAP services do not supply all the expected metadata) Ø We had some problems with the very large number of optional parameters (eg, coverage) in the registry and were unable to rely on these when querying the registry VODA - IVOA Victoria 17 May 2006

Why Plastic? Experiences. . . Ø Plastic is EASY and QUICK - only a few days were needed for a basic implementation of a connection with and between Plastic-enabled tools and VODA Ø Any new tools implementing certain messages in Plastic will automatically function with VODA Ø Plastic allows VODA to pass data references to visualization tools and also ingest VOTables from Plastic-enabled tools such as TOPCAT Ø You get a lot for free! Ø Next step is using Plastic-aware versions of tools like Astro. Scope/Data. Scope for the discovery phase VODA - IVOA Victoria 17 May 2006

VODA - IVOA Victoria 17 May 2006

Conclusions Ø VODA is a simple experimental implementation of the Virtual Directory concept Ø The use of Astro Runtime greatly eases access to multiple VO services Ø The use of Plastic allows very flexible and convenient two-way communication with other (powerful and mature) VO tools Ø The use of these elements, talking standard protocols, means that new VO tools may be quickly and easily developed in a modular way VODA - IVOA Victoria 17 May 2006