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Paper: Chapter 34: XML in the VO: VOTables
Volume: 382, The National Virtual Observatory: Tools and Techniques for Astronomical Research
Page: 363
Authors: Fitzpatrick, M.
Abstract: VOTable is an XML format for representing tabular data (the emphasis is on astronomical tables, but it is used for all forms of data interchange) in a uniform manner across all VO software and services. XML permits the use of industry standard tools and software and promotes interoperability, but more importantly allows the structuring of the rich set of metadata associated with the data, describing the columns of the table or an entire hierarchy of data.

VOTable was the first standard agreed upon by the IVOA, combining the best elements of familiar standards such as FITS with the need to efficiently exchange tabular data. Embedding the data within the document itself allows for the efficient exchange of small tables, but VOTable also has features such as remote and streaming data that make it suited for Grid computing as well. The immediate ancestors of VOTable are Astrores (developed at CDS) and the Extensible Scientific Interchange Language (XSIL, developed at Caltech), however there are many close similarities to the FITS Binary Table format. Indeed, though the transformation of a FITS Binary Table to a VOTable is meant to be a reversible operation, it is still possible to use all of the features of a VOTable to create a new document that cannot be converted to a FITS table without loss of information.

Each data table is known as a resource, and while in practice most VO services return only a single resource in response to a query, the format allows for an entire collection of associated resources to be exchanged. In this chapter we will discuss the VOTable document format and how it is commonly used with the goal of providing a better understanding of the format and how it might be used.

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