CF does a great job on describing datasets for general usage. But CF
leaves a gap on discovery metadata for data catalogs. Chapter 2.6.2
describes some, but not all parameters required by popular Discovery
Metadata-specifications like ISO19115 or DIF. This lead to several
CF-extensions, e.g.
* John Carons: Dataset Inventory Catalog Specification Version:
http://www.unidata.ucar.edu/projects/THREDDS/tech/catalog/InvCatalogSpec.html#controlledVocabulary
* Ethan Davis': NetCDF Attribute Convention for Dataset Discovery
http://www.unidata.ucar.edu/software/netcdf-java/formats/DataDiscoveryAttConvention.html
* Damocles (IPY) File specification
http://damocles.met.no/dokuwiki/lib/exe/fetch.php?id=documentation:start&cache=cache&media=documentation:deliverable_6_1_02b-metno.pdf
(chapter 6)
* others, e.g. adding a global attribute containing a ISO19115 metadata
xml-string.
The Dataset Inventory Catalog tells us to add discovery metadata to
external files, which is a bit against the netcdf-philosophy of bundling
metadata with the files. The other two examples add additional global
attributes to the files, which might lead to conflicts between (future)
CF versions and the added attributes.
CF should either include those attributes, or allow for a namespace for
an external document, i.e. following the NetCDF Attribute Convention for
DatasetDiscovery, adding a global attribute 'Metadata_Conventions' =
'...', and then all attribute starting with i.e. with 'MC_' should be
directed to the Metadata_Conventions parser.
Best regards,
Heiko
--
Dr. Heiko Klein Tel. + 47 22 96 32 58
Development Section / IT Department Fax. + 47 22 69 63 55
Norwegian Meteorological Institute http://www.met.no
P.O. Box 43 Blindern 0313 Oslo NORWAY
Received on Fri Jan 22 2010 - 03:34:32 GMT
