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: edavis@xxxxxxxx
P.O. Box 3000
Boulder, CO 80307-3000 http://www.unidata.ucar.edu/
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