IVOA Data Access Layer: roadmap as of year 2020

TL;DR

The paper reviews the progress and future plans of the IVOA Data Access Layer standards, focusing on interoperability, multi-dimensional data, and upcoming topics like No-SQL and parametric querying to support astrophysical data access.

Contribution

It provides a comprehensive summary of the current DAL standards, recent developments, and outlines future directions and topics for standardization in astrophysical data access.

Findings

DAL standards have addressed multi-wavelength and multi-dimensional data.

Recent updates include observation location and object visibility retrieval.

Future topics include No-SQL, code-to-data, and parametric querying.

Abstract

The IVOA works towards standardising interoperability and curation of data and service holdings of the global astrophysical community. Within the IVOA, the Data Access Layer (DAL) Working Group's goal is to provide technical standards for accessing data collections and catalogues; filtering data holdings based on their metadata; and retrieving the ones in scope, or operating on them. In recent years the DAL community has addressed the multi-dimensional and multi-wavelength scenarios, and kept core standards up-to-date. It has also tackled new topics such as the observation location and object visibility information retrieval, and payed back attention to outstanding topics like time domain and radio astronomy data. DAL work in the next few years will involve a mixture of revising existing standards, listening to feedback on recently updated and released standards, and defining new standards. Community feedback and contributions are needed for all DAL activities. Particularly important are the experiences of data providers and projects that are using VO technologies to address their scientific community's requirements. This is not a trivial task since the development of a standardised interface for the final user often requires more than one Recommendation to be implemented. This contribution aims to summarise the current DAL status and progress, in order to help new end-users understand how DAL can be beneficial. It also discusses the future changes to DAL standards and lists topics (No-SQL, code-to-data, parametric querying, actionable retrieval, ...) worth investigating in the future to keep access layer standardisation up to date with current needs.