XASLIB (was Re: data availability)
Hi Nino, Thanks for bringing this up and for the kind words. I agree that not only is access to measured XAFS spectra a problem now, it's been a problem for a long time, as evidenced by the Farrel Lytle database. In fact, it has long been a topic of discussion in the XAFS community of how to provide such databases, and developments over the past few years on data formats have been driven at least partly by the desire to have better spectral databases. For everyone: please try out XASLIB at http://cars.uchicago.edu/xaslib and let us know if you have any questions, comments, or suggestions for improving this database. Right now, there is not a lot of data here, but it is enough to give you an idea of how it works. Comments can either come here or as github Issues at the source repository for this code: https://github.com/XraySpectroscopy/XASDataLibrary There is a bit of documentation and wiki pages at https://github.com/XraySpectroscopy/XASDataLibrary/wiki A longer explanation: The standard XDI format for XAFS data (largely the work of Bruce) was presented at an IXAS workshop (Q2XAFS) in Tsukuba, Japan in 2011. At the most recent Q2XAFS meeting in Hamburg last August (as a satellite meeting of the XAFS conference), I presented an initial version of an on-line database based on this format, and intended for general use in the community. With feedback from that meeting, the version linked above is now ready for beta testing and comments. The plan is to move this to the IXAS Portal http://www.ixasportal.net/ixas/, but we'd like to get community suggestions and features and testing before we make that move. The database uses proper relational database to store the actual data, and tries to use modern web technologies for the interface. Some of the main features of this database are: - spectra can be uploaded from XDI files through the web interface. - multiple spectra can be tagged as belonging to the same Suite. - individual spectra or Suites can be rated and/or commented on by anyone, giving "Amazon-like" reviews. - in order to upload or comment, one has to log in by email address. The ratings and reviews are meant to provide some mechanism for data quality assurance, but to avoid having one person "police" the data before it can be added. This is trying to recognize that no one person can actually curate all the spectra, that truly bad data can be best identified by experts on that system, and also that there is actually some value to imperfect data. The requirements for data to be uploaded are fairly minimal except that the data must be in XDI format (basically so that metadata can be parsed easily and the columns are well-labeled), and that the monochromator lattice constant must be provided (so that energy re-calibration can be done if needed). We can help translate existing data into XDI so it can be uploaded into this database. There are several features to add or improve including: - adding some information about energy resolution. - being able to export a Suite of spectra as a single zip file or Athena project. - better web page interface to setting citation information. - better web page interface to setting sample information. But suggestions from anyone would be greatly appreciated. Finally, although the database is meant to provide a public, on-line databases useful to anyone, and uses modern relational database engines as the backend, the software can actually run on an individual machine to provide a local, private database of XAS spectra, with the same web-based interface. This is not very well documented at the moment, but if anyone is interested in trying to set such a database at their home institution, let me know. --Matt Newville
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Matt Newville