Browsing TAP services with TAPHandle

Mireille Louys (LSIIT/CDS), François Bonnarel (CDS), Grégory Mantelet (CDS), Laurent Michel (Observatoire Astronomique de Strasbourg)


Among all protocols promoted by the VO, TAP (Table Access Protocol) is certainly one of the best suited for data discovery. TAP does not constrain the nature of exposed data and allows data to be selected with an advanced query language : ADQL (Astronomical Data Query Language) .
A data discovery use case drawn up with VO users of the XMM-SSC team in Strasbourg highlights the scientific interest of such flexibility. The idea here is that the VO must help to evaluate the scientific relevance of some regions of the sky. The validation process consist in looking at as much data as possible in regards to that region. It relies on both VO tools (Aladin, Topcat..) and on flat-file previews (Readme, PDF, JPEG ...) for a quick view evaluation. If a region is considered as interesting, users download data-sets intended to be processed by their favorite reduction software which is usually not a VO tool. Downloaded data can either be simple files or file-set including for instance calibration data.
We present here TAPHandle, a tool designed to fulfill this request. TAPHandle is an AJAX application compatible with any Web browser and allowing to explore any table of any TAP service. TAPHandle works with a back-end server acting as a cache for all TAP services. This server side provides the Web application on demand with meta-data by using short JSON (JavaScript Object Notation) messages.
All TAP services accessed by TAPHandle are presented as one single browsable resource. This tool helps to explore tables exposed by a TAP service by showing the columns available. It proposes a smart ADQL editor enabling users to formulate queries without typing code and refine them in a simple text editor. A shopping cart service allows to download all interesting resources in one single ZIP file built in asynchronous mode.
The retrieved data files pass through a dynamic filter that binds data sets to appropriate applications according to their content description and access format. This uses either the IVOA SAMP (Simple Application Messaging Protocol) to share a file with VO aware applications or built-in Web browser features.

Paper ID: P087

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