characterizationaxis[axisframe/ucd=''pos'']/coverage/bounds/limits/stc:lolimit2vec/stc:c1/text() --> 308.512238

characterizationaxis[axisframe/ucd=''pos'']/coverage/bounds/limits/stc:lolimit2vec/stc:c2/text() --> 60.069312

characterizationaxis[axisframe/ucd=''pos'']/coverage/bounds/limits/stc:hilimit2vec/stc:c1/text() --> 308.798321

characterizationaxis[axisframe/ucd=''pos'']/coverage/bounds/limits/stc:hilimit2vec/stc:c2/text() --> 60.353806

characterizationaxis[axisframe/ucd='‘em'']/coverage/bounds/limits/stc:lolimit/text() --> 2.02 E10-6

mailto: louys@astro.u-strasbg.fr

Navigation within VO collections using XML metadata descriptions

Astronomical Spectroscopy and the Virtual Observatory Workshop,ESAC, March 2007

While studying a given observation the user wants to explore other VO data collections and request for other observations with similar or complementary properties.

• We offer a cross query mecanism based on the Characterisation metadata that can support various scenarii

oFrom an image look for IFU compatible data (this scenario)

oFrom a spectrum, search for images containing the observation position and with filters centered on some specific WL range (Ha), for instance

o From a 2D image search for other 2D images on different VO servers with fine selection criteria

1: Retrieve characterisation of an

Observation from a VO server and

visualise it using the CAMEA tool (*)

SELECT * FROM processed_data WHERE '//Chaxis[axisframe/ucd=''pos'']/coverage/location/coord/stc:position2d/value2/c1/text()‘ <= 308.798321

AND'//Chaxis[axisframe/ucd=''pos'']/coverage/location/coord/stc:position2d/value2/c1/text()‘ >= 308.512238

AND '//Chaxis[axisframe/ucd=''pos'']/coverage/location/coord/stc:position2d/value2/c2/text()‘ <= +60.353806

AND'//Chaxis[axisframe/ucd=''pos'']/coverage/location/coord/stc:position2d/value2/c1/text()‘ >= +60.069312

AND'//Chaxis[axisframe/ucd=''pos'']/axisframe/numbins2/i1/text()‘>1 AND'//Chaxis[axisframe/ucd=''pos'']/axisframe/numbins2/i2/text()‘>1 AND'//Chaxis[axisframe/ucd=''em'']/axisframe/numbins1/text()‘>1 AND'//Chaxis[axisframe/ucd=''em'']/coverage/location/coord/stc:spectral/stc:value/text()‘ <2.02e-06 ;

(*) Characterisation editing tool: (CAMEA: Characterisation for astronomical metadata Editing Application) : build up by CDS within the framework of VOTECH DS5) This application offers a user-friendly interface to browse, create or edit an XML metadata file compliant to the Characterisation schema. It supports all predefined axes: spatial, spectral, time, observable, but also allows for new axis definition.(#) http://alcor.sao.ru/php/search

F. Bonnarel 1, M. Louys 1, Igor Chilingarian 2,3, Ivan Zolothukin 3 , Brice Gassmann 1

(1) CDS, Strasbourg, (2) LERMA , Paris, (3) SAI, Moscow

Services supporting Characterisation Data Model can build a description of the physical content of their data. They express how Observations data values are spanned along physical axes and provide for each of these axes, assessments of properties of the data like the location, the limits or bounds, the resolution, etc. These metadata allow seeking for similar or complementary data in services supporting the same description.

2: Identify relevant metadata to search and filter out interesting data

3: Build up a request on these

criteria to Characterisation

compliant services

Derive proper Utypes to select other

observations

Define a metadata mask for query composition using Xpath syntax

Conclusion: Indexing the content of observational data of any dimension is now feasible in the VO, using existing data models such as the Characterisation and Spectrum data model via their Utypes representations

4: Get results from ASPID-SR database (#)

Characterisation of a 2MASS J image

3D-Spectroscopy

Bounds

2.16e 10-6

File

List XML

CharacterisationFITS

Headers

Spatial

Spectral

Find out 3D spectroscopy data falling within the bounds of our 2D image at shorter wavelength

Spectral Bounds

CAMEA : Characterisation editing tool