[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: catalog schema question: variable element



Hi Darren,

Darren Hardy wrote:
I have a question about the <variable> element in the inventory catalog schema. Suppose that I have the following information on a dataset variable (in DAS format):

Attributes {
    SST {
        String long_name "OI Cloud-free SST, blah blah blah";
        String standard_name "sea_surface_temperature";
        String units "degC";
    }
    Foobar {
        String long_name "My foobar variable"
        String units "m"
    }
}

As I read the catalog spec, I will lose the "human-readable" long_name attribute (ala CF-1.0):

<variables>
<variable name="SST" vocabulary_name="sea_surface_temperature" units="degC"/>
<variable name="Foobar" vocabulary_name"Foobar" units="m" />
</variables>
I think the mismatch is in our goals for the <variables> element. Our goal when designing the <variables> element was to provide a way to describe the variables in a dataset to a search service and allow users to add information that wasn't in the dataset. Since many search services require mapping variables to controlled vocabularies, we provided for a way to map dataset variable names into controlled vocabularies.

In your example, if you wanted to map the variables into the CF standard names, you could change the Foobar vocabulary_name to the appropriate CF standard name. So, if you knew that the Foobar variable mapped to CF standard name "sea_surface_height" you could edit your catalog to show this:

<variables vocabulary="CF-1.0">
<variable name="SST" vocabulary_name="sea_surface_temperature" units="degC"/>
<variable name="Foobar" vocabulary_name="sea_surface_height" units="m" />
</variables>


Of course, you could use your "long_name" entries as a controlled vocabulary of sorts like:

<variables vocabulary="myLongNames">
<variable name="SST" vocabulary_name="OI Cloud-free SST, blah blah blah" units="degC"/>
<variable name="Foobar" vocabulary_name="My foobar variable" units="m" />
</variables>


But either way you can't map all the information in your dataset. We have talked about allowing multiple mappings: either allowing multiple <variables> elements so that different vocabularies could be used; or moving multiple mappings into each <variable> element. But at this point we don't have that so in our schema.


Am I missing something? Is there a way to retain that human-readable description of the variables?
You can put it in the dataset description or keywords but that isn't quite as structured in terms of being specific to a variable.

Ethan

Thanks, -Darren


-- Ethan R. Davis Telephone: (303) 497-8155 Software Engineer Fax: (303) 497-8690 UCAR Unidata Program Center E-mail: address@hidden P.O. Box 3000 Boulder, CO 80307-3000 http://www.unidata.ucar.edu/ ---------------------------------------------------------------------------


=============================================================================== To unsubscribe thredds, visit: http://www.unidata.ucar.edu/mailing-list-delete-form.html ===============================================================================


NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.