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For the earth sciences there is a globally accepted standard - that is the NASA Directory Interchange Format (http://gcmd.nasa.gov/User/difguide/difman.html ), which is also FGDC and ISO 19115 compliant. It came out of the international Committee on Earth Observation and is the standard underlying the International Data Network, the US node of which is the Global Change Master Directory (GCMD). The GCMD/IDN is for earth science data the logical equivalent to OCLC's Worldcat. That standard has controlled vocabularies for many of the fields which are used as the basis for many of the ontologies that are in development for the earth sciences. While I agree completely with Joe about needing to know what services you need the metadata to support, I thought I would note that the DIF standard only has 8 required fields though the set of recommended fields is much longer... I've included the required fields below: Entry ID Entry Title Parameters (Science Keywords) ISO Topic Category Data Center Summary Metadata_Name Metadata_Version Ruth On Feb 24, 2009, at 12:59 PM, Stu Weibel wrote: > Hi, Joe, > >> I'm probably too close to this subject, as I've been working with the >> group developing SPASE, a metadata effort for describing the >> holdings of >> space physics archives, and there are some issues with what >> metadata is >> useful in different sub-communities, as well as some issues with >> terminology and how the different communities group their data into >> collections. >> ----- >> Joe Hourcle >> Principal Software Engineer >> Solar Data Analysis Center >> Goddard Space Flight Center > > Are your metadata standards available to the public? > > One of the things I'd like to see emerge from these discussions > would be a > lowest common denominator for data set metadata intended for > discovery, and > then specializations for particular domains. > > The structural metadata is a separate issue. I wonder if there is > likely to > be a coherent TYPE vocabulary for such data, and whether it can be > enumerated. Are there tens/hundreds/thousands of different > structure types > for such data? If there are tens or hundreds we have a chance of > TYPEing > them and providing managed schemas for them. > > Any feel for this based on your experiences? I can't speak for Joe, but in the earth sciences, the number of different data structures used is practically infinite. However, that said, there is some movement towards a smallish set of data formats that are in common use. However, even those "formats" are so complicated and variable that "TYPEing" them may be impossible (depending on the goal of "TYPEing"). netCDF and HDF (4 or 5) are two examples of these. > > > stu