John Caron wrote: ... > ----- Original Message ----- > From: "Joe Wielgosz" <address@hidden> ...
1) Don't restrict service types to known values. It is certain that people will want to add new service types, so the catalog format should be extensible in this area.
In order to prevent ambiguity (does "dods" equal "DODS" equals "distributed oceanographic data system"?) perhaps these types could somehow resolve to the url of the service's home page (e.g. DODS->http://unidata.ucar.edu/packages/dods). I don't know the most XML-savvy way to do this but perhaps the known mappings can be included in the DTD?
2) Same suggestion for metadata types.
In both these cases, the XML thing to do is to use a URI as a unique identifier. The options are eg:
Pros of 1: allows services to be added by anyone, URI optionally point to explanation Pros of 2: compact, explicitly documents allowable types
Say the THREDDS DTD contained the following:
<!NOTATION dods SYSTEM "http://unidata.ucar.edu/packages/dods"> <!NOTATION netcdf SYSTEM "http://unidata.ucar.edu/packages/netcdf"> <!ENTITY % standardMetadataTypes "dods | netcdf"> <!ATTLIST metadataRef metadataType NOTATION ( %standardmetadataTypes; ) #REQUIRED>
What do you think?
-- Joe Wielgosz address@hidden / (707)826-2631 --------------------------------------------------- Center for Ocean-Land-Atmosphere Studies (COLA) Institute for Global Environment and Society (IGES) http://www.iges.org
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.