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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



ID: 730393.0, MPI für Astronomie / Publikationen_mpia
Learning from FITS: Limitations in use in modern astronomical research
Authors:Thomas, B.; Jenness, T.; Economou, F.; Greenfield, P.; Hirst, P.; Berry, D. S.; Bray, E.; Gray, N.; Muna, D.; Turner, J.; de Val-Borro, M.; Santander-Vela, J.; Shupe, D.; Good, J.; Berriman, G. B.; Kitaeff, S.; Fay, J.; Laurino, O.; Alexov, A.; Landry, W.; Masters, J.; Brazier, A.; Schaaf, R.; Edwards, K.; Redman, R. O.; Marsh, T. R.; Streicher, O.; Norris, P.; Pascual, S.; Davie, M.; Droettboom, M.; Robitaille, T.; Campana, R.; Hagen, A.; Hartogh, P.; Klaes, D.; Craig, M. W.; Homeier, D.
Date of Publication (YYYY-MM-DD):2015
Title of Journal:Astronomy and Computing
Volume:12
Start Page:133
End Page:145
Audience:Not Specified
Abstract / Description:The Flexible Image Transport System (FITS) standard has been a great boon to astronomy, allowing observatories, scientists and the public to exchange astronomical information easily. The FITS standard, however, is showing its age. Developed in the late 1970s, the FITS authors made a number of implementation choices that, while common at the time, are now seen to limit its utility with modern data. The authors of the FITS standard could not anticipate the challenges which we are facing today in astronomical computing. Difficulties we now face include, but are not limited to, addressing the need to handle an expanded range of specialized data product types (data models), being more conducive to the networked exchange and storage of data, handling very large datasets, and capturing significantly more complex metadata and data relationships. There are members of the community today who find some or all of these limitations unworkable, and have decided to move ahead with storing data in other formats. If this fragmentation continues, we risk abandoning the advantages of broad interoperability, and ready archivability, that the FITS format provides for astronomy. In this paper we detail some selected important problems which exist within the FITS standard today. These problems may provide insight into deeper underlying issues which reside in the format and we provide a discussion of some lessons learned. It is not our intention here to prescribe specific remedies to these issues; rather, it is to call attention of the FITS and greater astronomical computing communities to these problems in the hope that it will spur action to address them. </ce:displayed-quote></ce:para>Of course, objects in astronomy are more likely to involve things like observations, instruments, celestial coordinates and actual astronomical objects such as stars. Likely properties one will encounter in a FITS file include things like observational parameters (start/end times), astronomical coordinates, name and properties of the observing instrumentation, and so forth. In FITS-speak, we can say that any FITS keyword outside those defined in the FITS standard is a data model parameter, and collections of related FITS keywords form a data model. Ideally a data model should be associated with a given, unique, "namespace" so that collisions in naming of the models and requisite parameters are avoided.</ce:para>Data models can provide a standard by which information (data and metadata) in the file may be semantically and syntactically validated in software. Questions such as "are all of the required metadata/data structures present in the file?" (e.g., all of the needed keywords occur in the correct places in the file) and "are there any non-normative values in the file?" (all metadata/data values are within expected bounds) are both questions answered by syntactic validation, the conformance of information in the file to one or more declared data models. The question of "how do these data (inter)relate with other data" (e.g., can named structures in the file be associated in some manner with others in another file/extension?) is one of semantic validation. By confirming that the file is 'valid' in both senses, we may link the data model to the information in the file, and hence answer the fundamental question "what does this data you gave me represent?" (e.g., lists of stars, tables of galaxies, images of dust clouds, etc.). It is important to note that all of these questions are critical to consumers of the file.</ce:para>There is already evidence that the FITS community values and needs shared data models. There are many examples. WCS and some other FITS conventions such as OIFITS (Thureau et al., 2006), MBFITS (Muders et al., 2006), PSRFITS (Hotan et al., 2004), SDFITS (Garwood, 2000) and FITS-IDI (Greisen, 2011) are data models. The declaration of keyword dictionaries4
Free Keywords:FITS; File formats; Standards
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:2213-1337
URL:http://cdsads.u-strasbg.fr/abs/2015A%26C....12..13...
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