Document Identifiers
Unique identifiers in metadata records are becoming more and more important for data citation and attribution and for identifying resources related to the resource being described in the metadata. Some mechanism must exist for ensuring that these identifiers are unique. This can be accomplished by using an identifier scheme that guarantees uniqueness (UUID) or by specifying the naming authority or namespace for the identifier. It is the responsibility of the manager of the namespace to ensure that the identifiers in that namespace are unique.
Metadata Record Identifiers
As metadata are shared between National and International repositories it is becoming increasing important to be able to unambiguously identify and refer to specific records. This requirement is facilitated by including an identifier for metadata record in the metadata itself.
Resource Identifiers
Metadata must include an unambiguous identifier for the resource that it describes.
Related Resource Identifiers
Metadata records increasingly refer to resources that are related to the resource being described. These external resources can be many different type of things.
ISO Identifiers
ISO 19115 identifiers include two elements: a code and an authority. The code is an alphanumeric value identifying an object in a namespace that is maintained by the authority. The authority is a CI_Citation. There is no agreed upon convention for describing a simple namespace in a CI_Citation. This problem was ameliorated by adding a codespace attribute to the RS_Identifier which could be substituted for MD_Identifier in 19115. This problem was addressed by adding three new CharacterStrings to the MD_Identifier class in ISO 19115-1 (the revision to 19115):
- codeSpace - which unambiguously defines the namespace for the identifier
- version - which is a version for the identifier
- description - a brief description of the meaning of the code
Crosswalks
Concept | Description | Dialect (Fit) Paths |
---|---|---|
Metadata Identifier | A phrase or string which uniquely identifies the metadata file/record. | ISO /*/gmd:fileIdentifier/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:metadataIdentifier/mcc:MD_Identifier DIF /dif:DIF/dif:Entry_Id |
Resource Identifier | Identifier for the resource described by the metadata | ISO /*/gmd:identificationInfo/*/gmd:citation/gmd:CI_Citation/gmd:identifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:citation/cit:CI_Citation/cit:identifier/mcc:MD_Identifier/mcc:code/gco:CharacterString ECHO /*/echo:DataSetId ECHO (1) /*/echo:ShortName | /*/echo:LongName DIF /dif:DIF/dif:Data_Set_Citation/dif:Dataset_DOI netCDF /nc:netcdf/nc:attribute[@nc:name=id]/@nc:value THREDDS /thredds:catalog/thredds:dataset/@ID ADIwg /adiwg:project/adiwg:idinfo/adiwg:ids/adiwg:projguid |
Related Resource Identifier | Identifier for a resource related to the resource being described. | ISO (1) /*/gmd:identificationInfo/*/gmd:aggregationInfo/gmd:MD_AggregateInformation/gmd:aggregateDataSetIdentifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO (1) /*/gmd:identificationInfo/*/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicDescription/gmd:geographicIdentifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO (1) /*/gmd:identificationInfo/*/gmd:processingLevel/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO (1) /*/gmd:dataQualityInfo/gmd:DQ_DataQuality/gmd:report/gmd:DQ_AccuracyOfATimeMeasurement/gmd:measureIdentification/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO (1) /gmi:MI_Metadata/gmi:acquisitionInformation/eos:EOS_AcquisitionInformation/gmi:operation/gmi:MI_Operation/gmi:identifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO (1) /gmi:MI_Metadata/gmi:acquisitionInformation/gmi:MI_AcquisitionInformation/gmi:platform/gmi:MI_Platform/gmi:identifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO (1) /gmi:MI_Metadata/gmi:acquisitionInformation/gmi:MI_AcquisitionInformation/gmi:instrument/gmi:MI_Instrument/gmi:identifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO /gmi:MI_Metadata/gmi:acquisitionInformation/eos:EOS_AcquisitionInformation/eos:sensor/eos:EOS_Sensor/eos:identifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:associatedResource/mri:MD_AssociatedResource/mri:name/cit:CI_Citation/cit:identifier/mcc:MD_Identifier/mcc:code/gco:CharacterString ECHO (1) /*/echo:CollectionAssociations/echo:CollectionAssociation/echo:ShortName ECHO (1) /*/echo:Spatial/echo:HorizontalSpatialDomain/echo:ZoneIdentifier ECHO (1) /*/echo:ProcessingLevelId ECHO (1) /*/echo:Campaigns/echo:Campaign/echo:ShortName | /*/echo:Campaigns/echo:Campaign/echo:LongName ECHO (1) /*/echo:Platforms/echo:Platform/echo:ShortName | /*/echo:Platforms/echo:Platform/echo:LongName ECHO (1) /*/echo:Platforms/echo:Platform/echo:Instruments/echo:Instrument/echo:ShortName | /echo:*/echo:Platforms/echo:Platform/echo:Instruments/echo:Instrument/echo:LongName ECHO (1) /*/echo:Platforms/echo:Platform/echo:Instruments/echo:Instrument/echo:Sensors/echo:Sensor/echo:ShortName | /*/echo:Platforms/echo:Platform/echo:Instruments/echo:Instrument/echo:Sensors/echo:Sensor/echo:LongName ECHO (1) /*/echo:AssociatedDIFs/echo:DIF/echo:EntryId |
Naming Authority | The organization responsible for the maintenance of the identifier (namespace) Note: DIF and ECHO use the Global Change Master Directory (GCMD) keywords. | ISO /*/gmd:identificationInfo/*/gmd:citation/gmd:CI_Citation/gmd:identifier/gmd:MD_Identifier/gmd:authority ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:citation/cit:CI_Citation/cit:identifier/mcc:MD_Identifier/mcc:codeSpace/gco:CharacterString netCDF /nc:netcdf/nc:attribute[@nc:name=naming_authority]/@nc:value THREDDS /thredds:catalog/thredds:dataset/@authority |
Parent Identifier | A unique identifier for a parent dataset or collection | ISO /*/gmd:identificationInfo/*/gmd:aggregationInfo/gmd:MD_AggregateInformation/gmd:aggregateDataSetName/gmd:CI_Citation/gmd:identifier/gmd:MD_Identifier/gmd:code/gco:CharacterString ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:associatedResource/mri:MD_AssociatedResource/mri:name/cit:CI_Citation/cit:identifier/mcc:MD_Identifier/mcc:code/gco:CharacterString DIF /dif:DIF/dif:Parent_DIF |
xPath Note: The xPaths included in this table use several wildcards. // means any path, so //gmd:CI_ResponsibleParty indicates a gmd:CI_ResponsibleParty anywhere in an XML file. /*/ indicates a single level with several possible elements. This usually indicates one of several concrete realizations of an abstract object. For example /*/gmd:identificationInfo could be gmd:MD_Metadata/gmd:identificationInfo or gmi:MI_Metadata/gmd:identificationInfo and gmd:identificationInfo//*/gmd:descriptiveKeywords could be gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords or gmd:identificationInfo/srv:SV_ServiceIdentification/gmd:descriptiveKeywords. Fit: The fit of the dialect path with the concept is estimated on a scale of 1 = excellent two-way fit, 2 = one-way fit or some other problem, 3 - extension required.