Difference between revisions of "Documenting Keywords"

From Earth Science Information Partners (ESIP)
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<Table width="60%" border="1" cellpadding="3" cellspacing="3" style="border-collapse: collapse;">
 
<Table width="60%" border="1" cellpadding="3" cellspacing="3" style="border-collapse: collapse;">
<tr><th width="30%">ISO</th><th width="30%">GCMD</th></tr>
+
<tr><th width="30%">ISO Keyword Types</th><th width="30%">GCMD Keyword Sets</th></tr>
 
<tr><td>discipline</td><td></td></tr>
 
<tr><td>discipline</td><td></td></tr>
<tr><td>place</td><td></td></tr>
+
<tr><td>place</td><td>Locations</td></tr>
 
<tr><td>statum</td><td></td></tr>
 
<tr><td>statum</td><td></td></tr>
 
<tr><td>temporal</td><td></td></tr>
 
<tr><td>temporal</td><td></td></tr>
<tr><td>theme</td><td></td></tr>
+
<tr><td>theme</td><td>Earth Science</td></tr>
<tr><td>dataCentre</td><td></td></tr>
+
<tr><td>dataCentre</td><td>Data Centers</td></tr>
 
<tr><td>featureType</td><td></td></tr>
 
<tr><td>featureType</td><td></td></tr>
<tr><td>instrument</td><td></td></tr>
+
<tr><td>instrument</td><td>Instrument/Sensors</td></tr>
<tr><td>platform</td><td></td></tr>
+
<tr><td>platform</td><td>Platforms/Sources</td></tr>
 
<tr><td>process</td><td></td></tr>
 
<tr><td>process</td><td></td></tr>
<tr><td>project</td><td></td></tr>
+
<tr><td>project</td><td>Projects</td></tr>
<tr><td>service</td><td></td></tr>
+
<tr><td>service</td><td>Data Services</td></tr>
 
<tr><td>product</td><td></td></tr>
 
<tr><td>product</td><td></td></tr>
 
<tr><td>subTopicCategory</td><td></td></tr>
 
<tr><td>subTopicCategory</td><td></td></tr>

Revision as of 13:56, November 17, 2014

Keywords are words or phrases that describe the metadata resource. They facilitate search, indexing and discovery of metadata, and are the largest single component of many metadata collections, regardless of the dialect. Keywords usually come from shared vocabularies in order to encourage consistency across metadata collections. Keywords can support text searches as well as facet searches.

GCMD

NASA GCMD keyword vocabularies ensure that metadata is described in a consistent manner. There are seven sets of controlled keywords in the GCMD directory: (1) Earth Science, (2) Data Services, (3) Data Centers, (4) Locations, (5) Instrument/Sensors, (6) Platforms/Sources, and (7) Projects.

GCMD Keywords are organized into hierarchical groups ranging from general Category Keywords to very specific Variable Level Keywords. The GCMD keywords include the following hierarchy levels; Category > Topic > Term > Variable Level 1 > Variable Level 2 > Variable Level 3 > Detailed Variable. Earth Science Keywords, also know as 'Theme' Keywords are highly recommended by most metadata dialects.

EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD DYNAMICS > MOISTURE FLUX > DOWNWARD MOISTURE FLUX

NASA Dialects

GCMD Keywords are required or recommended in the following NASA documentation dialects; Directory Interchange Format (DIF), Earth Observing System Clearinghouse (ECHO), Service Entry Resource Format (SERF) and Earth Observation System Data and Information Core System (ECS. Below are examples of Keyword documentation in each of these dialects.

ECHO

<ScienceKeyword>
    <CategoryKeyword>EARTH SCIENCE</CategoryKeyword>
    <TopicKeyword>ATMOSPHERE</TopicKeyword>
    <TermKeyword>ATMOSPHERIC CHEMISTRY</TermKeyword>
    <VariableLevel1Keyword>
        <Value>OXYGEN COMPOUNDS</Value>
        <VariableLevel2Keyword>
            <Value>OZONE</Value>
            <VariableLevel3Keyword>Keyword#3</VariableLevel3Keyword>
        </VariableLevel2Keyword>
    </VariableLevel1Keyword>
</ScienceKeyword>

DIF

SERF

ECS

ISO

The MD_Keyword object in ISO 19115-1.

<mri:descriptiveKeywords>
  <mri:MD_Keywords>
     <mri:keyword/>         // Keyword
     <mri:type/>            // Type of Keyword (Theme, Instrument, Place etc)
     <mri:thesaurusName/>   //Reference to the controlled vocabulary keyword source (GCMD)
     <mri:keywordClass/> 
  </mri:MD_Keywords>
</mri:descriptiveKeywords>

As noted above GCMD includes 7 Keyword Type Categories. ISO 19115-1 includes 15 Keyword Type Categories. The table below provides a reference list and mapping of GCMD and ISO Keyword Types

ISO Keyword TypesGCMD Keyword Sets
discipline
placeLocations
statum
temporal
themeEarth Science
dataCentreData Centers
featureType
instrumentInstrument/Sensors
platformPlatforms/Sources
process
projectProjects
serviceData Services
product
subTopicCategory
taxon

Crosswalks

ConceptDescriptionDialect (Fit) Paths
KeywordA word or phrase that describes some aspect of a resource. Can be one of several types.

Note: The general identification keywords usually have a type of "theme" and are refered to as "theme keywords". Other types and vocabularies are used for other information. Service Entry Resource Format (SERF) requires a Science and a Service GCMD Keyword. This concept is called "Subject" in the CSW Specification.
DIF (1) /dif:DIF/dif:Parameters/dif:Category
DIF (1) /dif:DIF/dif:Parameters/dif:Topic
DIF (1) /dif:DIF/dif:Parameters/dif:Term
DIF (1) /dif:DIF/dif:Parameters/dif:Variable_Level_1
DIF (1) /dif:DIF/dif:Parameters/dif:Variable_Level_2
DIF (1) /dif:DIF/dif:Parameters/dif:Variable_Level_3
DIF (1) /dif:DIF/dif:Parameters/dif:Detailed_Variable
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:CategoryKeyword
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:TopicKeyword
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:TermKeyword
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:VariableLevel1Keyword/echo:Value
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:VariableLevel2Keyword/echo:Value
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:VariableLevel3Keyword
ECHO (1) /*/echo:ScienceKeywords/echo:ScienceKeyword/echo:DetailedVariableKeyword
ECS (1) /*/ecs:DisciplineTopicParameters/ecs:DisciplineKeyword
ECS (1) /*/ecs:DisciplineTopicParameters/ecs:TopicKeyword
ECS (1) /*/ecs:DisciplineTopicParameters/ecs:TermKeyword
ECS (1) /*/ecs:DisciplineTopicParameters/ecs:VariableKeyword
SERF /serf:SERF/serf:Keyword
FGDC (1) /fgdc:metadata/fgdc:idinfo/fgdc:keywords/fgdc:theme/fgdc:themekey
ISO (1) /*/gmd:identificationInfo/*/gmd:descriptiveKeywords/gmd:MD_Keywords[gmd:type/gmd:MD_KeywordTypeCode='theme']/gmd:keyword/gco:CharacterString
ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:descriptiveKeywords/mri:MD_Keywords[mri:type/mri:MD_KeywordTypeCode='theme']/mri:keyword/gco:CharacterString
Keyword TypeMethods used to group similar keywordsISO /*/gmd:identificationInfo/*/gmd:descriptiveKeywords/gmd:MD_Keywords/gmd:type/gmd:MD_KeywordTypeCode
ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:descriptiveKeywords/mri:MD_Keywords/mri:type/mri:MD_KeywordTypeCode
Keyword VocabularyIf you are following a guideline or using a shared vocabulary for the words/phrases in your "keywords" attribute, put the name of that guideline here.

Note: DIF, ECHO and ECS require that theme keywords come from the Global Change Master Directory list.
ISO /*/gmd:identificationInfo/*/gmd:descriptiveKeywords/gmd:MD_Keywords[gmd:type/gmd:MD_KeywordTypeCode='theme']/gmd:thesaurusName/gmd:CI_Citation/gmd:title/gco:CharacterString
ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/*/mri:descriptiveKeywords/mri:MD_Keywords[mri:type/mri:MD_KeywordTypeCode='theme']/mri:thesaurusName/cit:CI_Citation
Keyword Vocabulary CitationName of the formally registered thesaurus or a similar authoritative source of keywords.ISO /*/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords/gmd:MD_Keywords/gmd:thesaurusName/gmd:CI_Citation
ISO /*/gmd:identificationInfo/srv:SV_ServiceIdentification/gmd:descriptiveKeywords/gmd:MD_Keywords/gmd:thesaurusName/gmd:CI_Citation
ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/mri:MD_DataIdentification/mri:descriptiveKeywords/mri:MD_Keywords/mri:thesaurusName/cit:CI_Citation
ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/srv:SV_ServiceIdentification/mri:descriptiveKeywords/mri:MD_Keywords/mri:thesaurusName/cit:CI_Citation
Keyword Ontology CitationReference that binds the keyword class to a formal conceptualization of a knowledge domain for use in semantic processing.ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/mri:MD_DataIdentification/mri:descriptiveKeywords/mri:MD_Keywords/mri:keywordClass/mri:MD_KeywordClass/mri:ontology/cit:CI_Citation
ISO-1 /mdb:MD_Metadata/mdb:identificationInfo/srv:SV_ServiceIdentification/mri:descriptiveKeywords/mri:MD_Keywords/mri:keywordClass/mri:MD_KeywordClass/mri:ontology/cit:CI_Citation

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.