Home

LOFAR archive

• website: https://lta.lofar.eu

How to get access

• create account, create affiliation -> follow instructions at login button
  • after creating account we cannot login: Could not login user to database http://db.lofar.target.nl
  • cannot change the password (username or password is not valid message)
• After reading the wiki, access needs to be granted by Science operations and support. This is not clear by following the login instructions
• We cannot find contact information in the contact list we find from following the wiki. We do find an adress using google.
• e-mail send to gain access / approve accounts

Observations when using the archive

• when using the search functionality on the lofar lta (https://lta.lofar.eu/Lofar?product=Simple&mode=query_page_object), if we put a location (ra/dec) it returns no results.

Useful links

• LOFAR LTA data access

  • web interface
  • web service
  • Python API

• Physics/astronomy-related standards, schemas, ontologies etc.

  • IVOA standards
    • VO concepts
    • VO applications
    • Ontology of Astronomical Object Types (OWL)
    • Astronomy Ontology (IVOAO_root)
  • Ontology of units of Measure (OM)
  • QUDT Ontologies for units of measure, quantity kind, dimensions and data types
  • FITS

• example catalogs:

  • Sloan digital sky survey (SDSS): http://www.sdss.org
  • Mikulski Archive for Space Telescopes (MAST): https://archive.stsci.edu/
  • Herschel Science Archive: http://archives.esac.esa.int/hsa/whsa/

• potential Linked/FAIR Data tools and services:

  • Virtuoso Universal Server (example instance)
  • FAIR Data Point (example instance)
  • grlc WebAPI
  • OpenRefine
  • EUDAT B2SAFE
  • EPIC PID
  • Zenodo

• other

  • Astropy

TODO

1. Get to know your data(sets) and use case.

• Which data are relevant or subject of this use case? (e.g. see LOFAR DBView)
• How do you access the (meta)data using which protocols?
• Which data can (not) be referred to by persistent IDs?
• In what formats are the data distributed?
• How are the data structured or organized? (e.g. catalog->dataset->distribution for use of the FAIR Data Point metadata service)
• Is this structure machine-readable? Suggestion: Install the (Python) FDP and try to fill in the config file.

2. Make the (meta)data available in a machine-readable and semantically interoperable format(s).

• Which domain-specific vocabularies and/or ontologies are relevant for this use case? (e.g. DCMI, DCAT, IVOA Ontology)
• Which terms (or URIs/IRIs) can be used to describe (identify) the data and associated metadata?
• "Semantify" the (meta)data i.e. transform into RDF and make these available through services.

Complementary Ideas

1. Improve the Search UI

• Create a bol.com styled faceted search
• Use an Oracle search interface
  • Application Express: https://apex.oracle.com/en/
  • Secure Enterprise Search: http://www.oracle.com/technetwork/search/oses/ses-twp-10-1-133183.pdf (page 10)
• ElasticSearch: https://www.elastic.co/products/elasticsearch + https://github.com/appbaseio/dejavu
• Apache Lucene + Solr: http://lucene.apache.org/solr/

2. Apply IVOA standards and tools

• The Virtual Observatory (VO) is the vision that astronomical datasets and other resources should work as a seamless whole. Many projects and data centres worldwide are working towards this goal. The International Virtual Observatory Alliance (IVOA) is an organisation that debates and agrees the technical standards that are needed to make the VO possible.
• Publishing Data into the VO: http://wiki.ivoa.net/twiki/bin/view/IVOA/PublishingInTheVO
• European VO software: http://www.euro-vo.org/?q=science/software
• TAP Service (the "Virtuoso" of Astronomy): http://saada.unistra.fr/taphandle/
• Search tool #1: http://svo.cab.inta-csic.es/docs/index.php?pagename=Projects/Astronomical_Data_Centres/Publishing including ConeSearch
• Search tool #2: https://github.com/csiro-rds/casda_vo_tools including ConeSearch, TAP etc.
• Search tool #3: http://ia2.oats.inaf.it/vo-services/vo-dance including ConeSearch, TAP etc.

Ontology-Schema Mapping

See Ontology page.

References

Wilkinson et al. (2016) The FAIR Guiding Principles for scientific data management and stewardship, Scientific Data, 3. doi: 10.1038/sdata.2016.18

Wilkinson et al. (2017) Interoperability and FAIRness through a Novel Combination of Web Technologies. PeerJ Computer Science, 3. doi: 10.7717/peerj-cs.110

Mons et al. (2018) Cloudy, increasingly FAIR; revisiting the FAIR Data guiding principles for the European Open Science Cloud. Information Services and Use, 37, 49-56. doi: 10.3233/ISU-170824