HELIO - Interoperability

The type of information included in files and the way that quantities are described differ making it difficult to combine them. Our work on semantics and ontologies (WPR1) is intended to address this issue, however, while semantic techniques can handle differences in the way things are described, they cannot address basic inadequacies in the metadata.

All virtual observatories should be able to provide access to existing data – it is not reasonable to expect providers to make changes to these data – but we should try to influence the quality of new data sets by encouraging the use of standards.

Through its Networking activities, HELIO is trying to develop new standards for data and metadata. This will not only make it easier to manage the observations in Virtual Observatories, but will also improve the situation for everyone.

Software has its own set of problems related to interoperability.

We can avoid some of them if the software can be executed as a set of independant modules – one for each domain – that communicate through intermediate files. However, the problems start when users want to compare data from several domains and the software needs to be combined into a single analysis environment.

Many domains are using Interactive Data Language (IDL), which gives a degree of commonality, and IDL can also interface with modules written in other languages. But often the routines have been named without giving a though to interoperability, and collisions can occur.

SolarSoft has had to address these problems since it includes branches for many observatories and instruments and it has procedures for identifying and resolving conflicts. These techniques would need to be applied in the more general case and we will need to talk to the organizations involved.

We welcome input from anyone that is interested in contributing to this activity. If you are interested in participating, email user_groups(at)helio-vo.eu

The CASSIS project is also intended to address these issues.