Articles from Meetings

  • Asterics Tech Forum

    The 3. Asterics DADI Tech Forum took place last week in Strasbourg - and many GAVO members made contributions as well. This time, there were 3 slots for hackathon sessions, which were also used for discussions. We'll mention two highlights of our contributions here.

    We took the opportunity to push our Provenance Data Model efforts and used the hackathon slots for provenance discussions.

    One topic was the links between the simulation data model and ProvenanceDM, and how to map from SimDM to ProvenanceDM classes. This mapping works quite well and will be included in the working draft for the data model. We also had an interesting talk by José Enrique Ruiz on his view on Provenance, workflows, and - very important - the "deployer" and "system" provenance for storing all the environment variables that may be needed to rerun the processing of some observational data. Michèle Sanguillon also presented for the first time her extension to the prov Python library (W3C) with extensions from our IVOA Provenance Data Model. We also had interested people from outside the usual provenance-interested people joining in, e.g. from the Astron project. More about our Provenance modelling efforts can be found at IVOA Provenance wiki page.

    A world premiere (of sorts) was the first discussion of RegTAP 1.1. RegTAP is a search interface to the VO Registry; it is what TOPCAT or other VO clients uses when you type in keywords to locate services. A fairly direct web-basd interface is our WIRR registry interface. RegTAP will need a bit of a makeover since VOResource, the underlying metadata scheme is currently receiving one, allowing, in particular, for including DOIs and ORCIDs (John Does of this world, rejoice: People can finally uniquely find your data and not that of all the other J. Does) in Registry records and figuring out licenses on data. Licensing may not matter when you use data in a paper but it does matter if you want to redistribute data, e.g. for planetarium programs with catalog data or pretty pictures, or when re-mixing data.

    But of course the GAVOistas happily joined the fray on the many other topics discussed, from a standard format for a time series to interoperable authentication, from datalink applications to figuring out if data coming into a program should be treated as a collection of spectra or rather an object catalog – the latter in the context of the upcoming version 10 of the VO's premier image tool Aladin, which we saw (probably another premiere) demoed. We can already promise you an exciting update!

  • And the Solar System, too

    Virtual Observatory technologies are increasingly being adopted outside of “core” astronomy in the vicinity of the optical band (to which they have had, I'll have to admit, a certain slant) . An excellent example for that trend is the Europlanet community. Their goal is to make solar system data accessible without fiddling, and they are employing a wide range of VO standards for that. At the heart of their efforts are TAP and the VO Registry.

    While the usual VO client software will of course work fine with their services, they are offering a nice web-based discovery tool executing queries against an increasing number of services. Such uniform quering over many services is possible is because all of them implement TAP and host EPNcore tables. The resulting interface, also known as EPN-TAP, allows for very flexible discovery and retrieval of solar system data products, much like ObsTAP does for astronomical observations outside of the solar system.

    Since quite a few EPN-TAP services are built using GAVO's DaCHS publication suite, I was invited to this week's VESPA implementation workshop 2017 in Graz to help the data providers set up their services.

    I can't deny that I'm somewhat excited when I see how our software is used to publish spectra of the ice blocks in Saturn's ring taken by the lonely Cassini spacecraft still orbiting the gas giant, or data transmitted by Rosetta, now (and for who knows how long) sitting on comet 67P/Churyumov-Gerasimenko. There's even an upcoming archive of solar system alerts that may, according to its builders, include events like meteor showers on Mars. I can almost hear my code whisper “I've archived signals of C-beams glitter in the dark near the Tannhäuser Gate”.

    Even documentation can become otherworldly in this business: Already in February, DaCHS has learnt to procude GeoJSON, a format common in the GIS community and also adopted by Europlanet – planetology has lots of common ground with geoinformatics. And in the reference documentation on annotating tables to enable that, when I wrote “standards-compliant GeoJSON clients will interpret your coordinates as WGS84 on Earth if you leave [frame annotation] out”, I was severely tempted to add “which is probably not what you want” and feel like Spaceman Spiff.

    Romantic space adventures aside, after this intense week, not only are there several additional or improved EPN-TAP services from places ranging from Pasadena to Villafranca to Warsaw in the pipeline, the close interaction with the data providers has also led to very significant improvements to DaCHS' EPN-TAP support. The tutorial chapter on EPN-TAP and the reference documentation linked from there already reflect the results of this workshop. You'll need a current DaCHS beta package for that to work, though; we expect this stuff to go into our release packages around July.

    If any of the workshop participants read this: Thanks a lot for your patience with DaCHS' sometimes somewhat cryptic diagnostics. If, on the other hand, you missed the Graz workshop and have solar system data: Please talk to us or the kind and friendly Europlanet folks – either us will be delighted to support your publication project. And perhaps we'll meet you at the next such workshop, planned for 2018 in the Czech Republic.

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