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EuroVO Workshop 2005

27 June – 1 July 2005
ESO Headquarters, Munich, Germany

This page was used during the preparation of the workshop is now obsolete. Software and documentation is available from the public pages.

Infrastructure

• up to 2 desktop PCs, one running Windows XP Pro (SP2) and the 2nd optionally with Linux RedHat Fedora Core 3
• 2 17" monitors
• 1 beamer (connected to the Windows machine)
• Java J2SE v1.4.2

Wireless internet connection will be available.

Overview Talks details (abstract)

IVOA Standards Status & Architecture

The International Virtual Observatory Alliance (IVOA) is the leading global forum which defines the common technical roadmap of the VO projects and drives the standardization process of its infrastructure.

Federating the numerous legacy systems and data in the various sub disciplines of Astronomy in a common framework is a true challenge. The IVOA structure, it's procedures and the status on the way to a common framework architecture are outlined in this presentation.

-- MarkusDolensky

Lectures↔Tutorials Relationship

Lecture details (abstract)

SIAP/SSAP

Part 1: Data Access layer protocols describe how astronomical data services can be requested and what is the format of the Query Reponse and Retrieval of the data services.

• Cone search describe the queries to catalog services
• SSA describes Spectra services (see Pedro Osuna lecture)
• Simple Image Access is mainly dedicated to 2D images
• The current IVOA standard is SIA 1.0

An exhaustive presentation of the standard will be given with discussion of implementation tricks.

In a second part of the lecture hints will be given on the general trends for the next version planned for the end of 2005, with inclusion of characterization data model utypes and possibility to use a metadata extension mechanism.

Pointers towards P. Osuna's lecture on SSA will be given.

-- FrancoisBonnarel

Part 2: Simple Spectrum Access Protocol (SSAP) is an emerging protocol of the International Virtual Observatory Alliance (IVOA). The initital protocol design was very much inline with the SIAP protocol (see F. Bonnarel presentation). This initial attempt protocol will be presented in the DAL tutorial as a very successful proof of concept of the usefulness of Spectral access in the VO context. A more complex implementation of the SSA protocol has seen the light recently at the last IVOA meeting in Kyoto, Japan, and has been given the first official version 0.9.

This lecture will explain the initial SSAP concept and the more advanced SSAP version 0.9 with related SSA and SED Data Model information.

-- PedroOsuna

Presentation: (.pdf), (.ppt)

ADQL/Skynode:

ADQL (Astronomical Data Query Language) is an XML query language based on SQL. It also includes some support to astronomical region search and cross matching. Among the different services making use of this language emerged the IVOA SkyQuery which was implementing a distributed query system using Microsoft Technology.

The original prototype was using proprietary technology and some efforts have been done to make it properly platform and implementation independent since then. For this purpose the protocol has been opened and as a result of it a new architecture has been brought up including OpenSkyQuery Portal, IVOA SkyNodes and ADQL support. The IVOA SkyNode Interface consists on two different levels: The minimum SkyNode Interface, so called Basic Skynode Interface, allows basic ADQL support (circular region search plus basic queries with data returned) while the Full SkyNode interface aims to perform Catalog Cross Matching between nodes and complex shape region searches.

Recently ESAC has build up the Full SkyNode implementation in pure Java and standard astronomical coordinates. We will present at this lecture all the goals achieved, the current status of this implementation and further actions to be taken to open the standard as much as possible.

-- Inaki Ortiz

Presentation: (.pdf), (.ppt)

VOTable:

VOTable is an XML standard for the interchange of data structured as a set of tables mainly designed to deal with astronomical data. A table is a set of rows, each of them with an uniform format, defined in the table metadata. Each row of the table is a set of cells. each of them containing a primitive data type or an array of primitive data types.

Designed in the Virtual Observatory framework, one of the main objectives at the moment of the VOTable standard definition was to assure the compatibility with the most commonly used format for astronomical data storage: FITS. In a VOTable file it is possible to either encapsulate a FITS file into the VOTable or just to define its contents in the metadata and provide a link to the actual file as a remote resource.

VOTable is by the time being stable and well accepted by the VO community. It is the standard output format for VO protocols such as ConeSearch, SIAP or SSAP, and several tools have been developed in the VO framework to deal with data in VOTable format: VOPlot, Topcat, Aladin, etc. A set of parsers is also available for developers in different programming languages to create new applications able to work with data in VOTable format: savot, javot, etc.

-- RaulGutierrez

Presentation: (.pdf), (.ppt)

Metadata/UCD:

UCDs (Unified Content Descriptors) provide a standardized semantic description of astronomical contents. UCDs are therefore a very important piece of metadata for describing data contents. They allow interoperability between different data providers and service consumers in the VO.

We will first present the history, philosophy and syntax rules to build UCDs, and the list of standard words in the vocabulary. Then we will learn how to apply UCDs in various contexts (VOTable, Registry, DAL).

The management of UCDs on the data provider's side will be discussed, and tools for assigning and maintaining UCDs will be presented. We will also show how UCDs can be used in VO applications, in particular for automated quantity recognitions.

-- SebastienDerriere - 25 May 2005

Presentation: (.pdf), (.ppt)

Grid/Web Services:

Web services are a useful way of formalizing machine-to-machine communications in the IVO. They are more powerful than general HTTP services and correspondingly harder to use. The lecture explores the benefits and costs of using web services and emphasizes the advantages of standard web-service contracts.

The following points will be covered.

Part one: a general introduction to web services:

• The definition of a web service, and how it differs from a simple HTTP service.
• WSDL contracts and SOAP clients.
• SOAP tool-kits and containers for SOAP services.
• Situations when a SOAP service may be the best architectural choice.

Part two: stateful web services:

• The concept of stateful services and their use in the IVO and 'the grid'.
• Old-style (OGSI) and new-style (WS-RF) grid services.

Part three: Euro-VO and IVOA standards for web services:

• Standards applying to all services.
• Standard WSDL contracts for specific services, current and future.
• CEA: a standard WSDL contract for abitrary applications.

Presentation: (.pdf), (.ppt)

Registry:

Registry contains detailed information about all the resources (data and applications) in the Virtual Observatory (VO). Users, applications, and components query the registry to find and access resources. The registry is a key component of many applications since all 'resource discovery' must happen through the registry.

Some of the key information available through the registry includes:

• How and where to run data access services such as cone searches and other queries;
• How and where to run applications such as sextractor, hyperz, and the AstroGrid solar movie maker;
• The coverage and other metadata relating to a dataset and the names of tables and columns within it;
• The location of other Registries around the world.

A registry supports a standard Query interface which allows applications and components to submit queries in a standard form and so discover relevant resources. All registries around the world are synchronised (via OAI-style harvesting) to keep the information coherent and complete. We will present in this lecture a more detailed view of the registry and how it works, its current status in the IVOA, and where the registry is going in the future.

-- KevinBenson

Presentation: (.pdf), (.ppt)

Data Centre Infrastructure:

Key to the success of the Virtual Observatory is access to a wide range of heterogenous astronomical data. Such access must be consistent and predictable across all storage mechanisms (database, flat files, image etc).

Our lecture will present a brief overview of data access in an IVOA context and look at some of the solutions currently in place. We will show in detail the AstroGrid Data Set Access component which provides IVOA compliant interfaces to a wide variety of datasets. Its plugin architecture allows it to be extended to provide interfaces to new IVOA standards as they emerge and new data storage mechanisms as they are encountered. By default, DSA supports a variety of interfaces (ADQL, CEA, SSAP, etc) and can access most databases that have a JDBC driver (PostgreSQL, MySQL, MicroSoft SQLServer, etc) as well as flat files and images.

In the tutorial, attendees will have the opportunity to install and configure the AstroGrid DSA component against a real dataset (most probably a limited extract of a well known dataset - USNO-B or 2MASS in either a PostgreSQL or MySQL database). The tutorial will also cover how such a deployment is registered and tested.

Presentation: (.pdf), (.ppt)

Demo details

Please upload the software required to run the demo to this page if the size of the zipped tarball is ≤ 50MB. Otherwise provide a link for download.
In case of using commercial software or other proprietary material, please provide the necessary information on how to obtain it.

Applications:

Virtual Observatory applications are rapidly maturing into useable scientific tools. The use of VO standards for easy access to images, spectra, catalogues and services is opening up new ways of doing astronomy, bringing down the interoperability barriers. Here we present and demonstrate a set of VO applications, from the various European and international VO projects, using some simple scienctific examples. We highlight where the standards are being used, and the benefits of these standards for making tools work together. Being early days for the VO, many tools are in the prototype phase, and we emphasize how the real life experience of using prototype tools helps drive the development of the standards, and keeps the VO in check with astronomy goals.

-- MarkAllen & ThomasBoch

Presentation: (.pdf), (.ppt)

Software:

Xmatch/Classification: ...abstract...

Presentation: (.pdf), (.ppt)

Software:

Tutorial & Demo details (abstract + software + special requirements)

Please upload the software required to run the tutorial to the appropriate page (see list) if the size of the zipped tarball is ≤ 50MB. Otherwise provide a link for download.
In case of using commercial software or other proprietary material, please provide the necessary information on how to obtain it.

If possible, in order to limit the dependencies on external services, then it would be best if the local ESO installed Astrogrid components from the Avo Demo 2005 were used (details here).

The entry below is a short example that hopefully makes clear what is required in the table columns for software requirements. The local table is intended to list any software that the tutor will need loaded onto the demonstration machines, and will be given to the participants on the workshop CD - together with the necessary documentation and the trial data. The entries in the remote table are intended to make clear any external service dependencies that are also necessary for the correct functioning of the tutorial. The columns should be completed as follows:

• Name/Version The name and version of the software.
• Location Either a link to where the software can be downloaded from, or a reference to the uploaded software on this wiki page.
• Preferred OS The operating system that the software has to run under - if no preference is given then windows XP will be assumed.
• Notes Any other information that you think will be important to the correct functioning of the software.
• Service Type A description of the remote service.
• Service URL A link to the endpoint of the service.
• Service Admin The person that will be responsible for ensuring that the service will be available for the duration of the workshop.

Contact: PaulHarrison

Software:

Tutorial Pages

Template for Presentations

• .ppt
• .sxi

Template for Tutorial Guidelines

• .html

Software Distribution

A page for collecting feedback has been created: please feel free to add your ideas (comments, suggestions, bugs, etc.) about the workshop software.

Pics