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