Difference between revisions of "Data Set Identifiers and other Unique IDs"
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Latest revision as of 14:57, 13 May 2013
A dataset identifier should be a globally unique value that is associated with an individual metadata record.
Best practices for creating unique dataset identifiers
- For the "global" part of the ID, use lowercase reversed domain name "namespace" before a colon, ":"
- Optionally add before the colon the group/division/entity in charge of the metadata
- The global part doesn't have to be a working URL, but it's a good idea if it is
- Use alpha numeric values only, plus underscore, "_"
- No commas, dashes, other funky symbols
- No spaces
Note that unique IDs are often used in URLs or file names on various operating systems. While it's not required to follow all these syntax rules in every case, you'll see fewer problems and wider distribution for your metadata if you do.
When a record is published to EMS, the "global" part of the Dataset ID before the colon is used to identify the web directory where the metadata record can be found. So the global part if the ID must be the same for all records in a single record set. This global ID should be decided upon at the time of creation of the record set, and must be different from all other record sets. (It can be changed later, but this change must be done to all records, and can result in broken links if any URLs have been given out which included the old global ID.)
List of elements that use unique ids in FGDC standard
|In Identification Information Section|
|Dataset Identifier||Globally unique value that identifies a particular metadata record.||idinfo/datsetid||RSE|
|DEPRECATED! DO NOT USE. Unique value that identifies a particular metadata record.||noaainfo/entry||NOAA|
|Citation Identifier||At this Xpath, this is the same as the <datsetid> value.||idinfo/citation/citeinfo/citId||NGDC|
|Dataset Identifier of Container Packet||Identifier of aggregation of which dataset is member, aka the <datsetid> of a related metadata record.||idinfo/agginfo/conpckid/datsetid||RSE|
|Dataset Identifier of Component/Aggregation Member||Identifier of component of a dataset, in other words the <datsetid> of a related metadata record.||idinfo/agginfo/compinfo/aggmemid/datsetid||RSE|
|In Data Quality Section|
|Source Citation Abbreviation||Unique value that represents source data in Lineage. Same value as */citeinfo/citId.||dataqual/lineage/srcinfo/srccitea||FGDC|
|Source Used Citation Abbreviation||Unique value that represents source data in Process Steps.||dataqual/lineag/procstep/srcused||FGDC|
|Source Produced Citation Abbreviation||Unique value that represents source data in Process Steps.||dataqual/lineag/procstep/srcprod||FGDC|
|In Distribution Information Section|
|Resource Description||The identifier by which the distributor knows the data set.(Does not have to be unique.)||distinfo/resdesc||FGDC|
|Resource Description||The identifier by which the distributor knows the data set.Does not have to be unique. Added to accomodate for different standard order details.||distinfo/stdorder/resdesc||NGDC|
|In Various Sections|
|Citation Identifier||Uniquely identifies the entity represented in the Citation Information section.||*/citeinfo/citId||NGDC|
The 'Source' is the standard or community from which the metadata element originates.
RSE - Content Standard for Digital Geospatial Metadata: Extensions for Remote Sensing Metadata, FGDC-STD-012-2002.
NOAA - NOAA Supplemental, an outdated local extension for NOAA metadata.
FGDC - Content Standard for Digital Geospatial Metadata (version 2.0), FGDC-STD-001-1998.
ISO - Local extensions adopted from ISO 19115 by the metadata community at NGDC.
The <entry> element is a part of the NOAA Supplemental section. It is not part of a recognized FGDC standard, and is being phased out in favor of the Remote Sensing Extensions (RSE) standard Dataset Identifier element. Many of our newer metadata records do not have this value, and older records should not maintain it.
--Ashah 14:57, 13 May 2013 (MDT)