The International Virtual Observatory Alliance (IVOA: http://www.ivoa.net) represents 14 international projects working in coordination to realize the essential technologies and interoperability standards necessary to create a new research infrastructure for 21st century astronomy. This international Virtual Observatory will allow astronomers to interrogate multiple data centres in a seamless and transparent way, will provide new powerful analysis and visualisation tools within that system, and will give data centres a standard framework for publishing and delivering services using their data. The first step for the IVOA projects is to develop the standardised framework that will allow such creative diversity. Since its inception in June 2002, the IVOA has already fostered the creation of a new international and widely accepted, astronomical data format (VOTable) and has set up technical working groups devoted to defining essential standards for service registries, content description, data access, data models and query languages following developments in the grid community. These new standards and technologies are being used to build science prototypes, demonstrations, and applications, many of which have been shown in international meetings in the past two years. This paper reviews the current status of IVOA projects, the priority areas for technical development, the science prototypes and planned developments.
Visualisation is a powerful tool for understanding the large data sets
typical of astronomical surveys and can reveal unsuspected
relationships and anomalous regions of parameter space which may be
difficult to find programatically. Visualisation is a classic
information technology for optimising scientific return. We are
developing a number of generic on-line visualisation tools as a
component of the Australian Virtual Observatory project. The tools
will be deployed within the framework of the International Virtual
Observatory Alliance (IVOA), and follow agreed-upon standards to make
them accessible by other programs and people. We and our IVOA
partners plan to utilise new information technologies (such as grid
computing and web services) to advance the scientific return of
existing and future instrumentation.
Here we present a new tool - VOlume - which visualises point data.
Visualisation of astronomical data normally requires the local
installation of complex software, the downloading of potentially large
datasets, and very often time-consuming and tedious data format
conversions. VOlume enables the astronomer to visualise data using
just a web browser and plug-in. This is achieved using IVOA standards
which allow us to pass data between Web Services, Java Servlet
Technology and Common Gateway Interface programs. Data from a
catalogue server can be streamed in eXtensible Mark-up Language format
to a servlet which produces Virtual Reality Modeling Language output.
The user selects elements of the catalogue to map to geometry and then
visualises the result in a browser plug-in such as
Cortona or FreeWRL.
Other than requiring an input VOTable format file, VOlume is very
general. While its major use will likely be to display and explore
astronomical source catalogues, it can easily render other important
parameter fields such as the sky and redshift coverage of proposed
surveys or the sampling of the visibility plane by a