Science Keywords

Element Description

The science keyword elements enable the specification of Earth science keywords related to the data set. The science keywords are chosen from a controlled keyword hierarchy maintained in the Keyword Management System (KMS). A list of valid science keywords can be found here: https://gcmdservices.gsfc.nasa.gov/static/kms/sciencekeywords/sciencekeywords.csv?

Best Practices

Science keywords are important for the precise search and retrieval of data, and should accurately represent the data set being described. As a rule of thumb, science keywords should represent the scientific parameters being provided in the data as well as any broader conceptual terms that may aid in describing the data. At a minimum, one science keyword hierarchy must be provided, and this hierarchy must go down to the 'Term' level of detail. The 'Detailed Variable' element is the only science keyword element that is not controlled by the KMS. The 'Detailed Variable' keyword should only be used if there is a very specific parameter provided in the data which is not adequately described by keywords in the KMS. If a particular science keyword is missing from the KMS, it is possible to put in a request to have it added. The KMS is managed by the Global Change Master Directory (GCMD) and new keyword requests may be made through the GCMD Keywords Community Forum.

All positions in the science keyword hierarchy must be populated until the desired level of detail is reached. Skipping or leaving blank a position in the keyword hierarchy will render the keyword invalid. The only exception to this is the 'Detailed Variable' element; a Detailed Variable keyword may be provided as long as it is preceded by the required Category, Topic and Term keywords. Science keywords are not case sensitive.

Examples:

ScienceKeywords/Category: "EARTH SCIENCE"

ScienceKeywords/Topic: "ATMOSPHERE"

ScienceKeywords/Term: "CLOUDS"

ScienceKeywords/VariableLevel1: "TROPOSPHERIC/LOW LEVEL CLOUDS (OBSERVED/ANALYZED)"

ScienceKeywords/VariableLevel2: "STRATOCUMULUS"

ScienceKeywords/VariableLevel3: "STRATOCUMULUS CUMILIFORMIS"

ScienceKeywords/DetailedVariable: "STRATOCUMULUS VESPERALIS"

ScienceKeywords/Category: "EARTH SCIENCE"

ScienceKeywords/Topic: "BIOSPHERE"

ScienceKeywords/Term: "ECOLOGICAL DYNAMICS"

ScienceKeywords/VariableLevel1: "FIRE ECOLOGY"

ScienceKeywords/VariableLevel2: "FIRE MODELS"

Element Specification

An unlimited amount of science keywords may be listed (Cardinality: 1..*)

Model	Element	Type	Constraints	Required?	Cardinality
UMM-C	ScienceKeywords/Category	String	KMS controlled	Yes	1
UMM-C	ScienceKeywords/Topic	String	KMS controlled	Yes	1
UMM-C	ScienceKeywords/Term	String	KMS controlled	Yes	1
UMM-C	ScienceKeywords/VariableLevel1	String	KMS controlled	No	0..1
UMM-C	ScienceKeywords/VariableLevel2	String	KMS controlled	No	0..1
UMM-C	ScienceKeywords/VariableLevel3	String	KMS controlled	No	0..1
UMM-C	ScienceKeywords/DetailedVariable	String	Uncontrolled (Free-Text)	No	0..1

ARC Priority Matrix

Priority Categorization	Justification
	This element is categorized as highest priority when: The element is not included at all. The element is included but is empty. The science keyword does not align with the KMS. The science keyword does not exist in KMS. A keyword(s) is missing from the hierarchy. A keyword(s) is placed in the incorrect position of the hierarchy (e.g. a Variable Level 2 keyword is placed in the Variable Level 1 field). The science keyword is not appropriate for the dataset.
	This element is categorized as medium priority when: A recommendation is made to add a relevant science keyword to the metadata. A recommendation is made to add to an existing keyword in the metadata (i.e. i.e. to extend a keyword hierarchy down to a more detailed keyword).
	Not Applicable
	The element is provided, and follows all applicable criteria specified in the best practices section above.

Dialect Mappings

DIF 9

DIF 9 ^{(Note: DIF-9 is being phased out and will no longer be supported after 2018)}

DIF 10

DIF 10

An unlimited amount of science keywords may be listed (Cardinality: 1..*)

Specification	Path	Type	Constraints	Required in DIF 10?	Cardinality	Notes
DIF 10	/DIF/Science_Keywords/Category	String	KMS controlled	Yes	1	The category keyword will always be "EARTH SCIENCE"
DIF 10	/DIF/Science_Keywords/Topic	String	KMS controlled	Yes	1
DIF 10	/DIF/Science_Keywords/Term	String	KMS controlled	Yes	1
DIF 10	/DIF/Science_Keywords/Variable_Level_1	String	KMS controlled	No	0..1
DIF 10	/DIF/Science_Keywords/Variable_Level_2	String	KMS controlled	No	0..1
DIF 10	/DIF/Science_Keywords/Variable_Level_3	String	KMS controlled	No	0..1
DIF 10	/DIF/Science_Keywords/Detailed_Variable	String	Uncontrolled (Free-Text)	No	0..1

Example Mapping

DIF 10

<Science_Keywords>
  <Category>EARTH SCIENCE</Category>
  <Topic>BIOSPHERE</Topic>
  <Term>VEGETATION</Term>
  <Variable_Level_1>VEGETATION INDEX</Variable_Level_1>
  <Variable_Level_2>NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)</Variable_Level_2>
  <Detailed_Variable>0.9 DENSITY</Detailed_Variable>
</Science_Keywords>
<Science_Keywords>
  <Category>EARTH SCIENCE</Category>
  <Topic>BIOSPHERE</Topic>
  <Term>VEGETATION</Term>
  <Variable_Level_1>EVERGREEN VEGETATION</Variable_Level_1>
</Science_Keywords>

UMM

ScienceKeywords: [
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "VEGETATION INDEX"
    VariableLevel2: "NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)"
    DetailedVariable: "0.9 DENSITY"
  },
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "EVERGREEN VEGETATION"
  }
],

ECHO 10

ECHO 10

An unlimited amount of science keywords may be listed (Cardinality: 1..*)

Specification	Path	Type	Constraints	Required in ECHO10?	Cardinality	Notes
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/CategoryKeyword	String	KMS controlled	Yes	1	The category keyword will always be "EARTH SCIENCE"
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/TopicKeyword	String	KMS controlled	Yes	1
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/TermKeyword	String	KMS controlled	Yes	1
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/VariableLevel1Keyword/Value	String	KMS controlled	No	0..1
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/VariableLevel1Keyword/VariableLevel2Keyword/Value	String	KMS controlled	No	0..1
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/VariableLevel1Keyword/VariableLevel2Keyword/VariableLevel3Keyword/Value	String	KMS controlled	No	0..1
ECHO 10	/Collection/ScienceKeywords/ScienceKeyword/DetailedVariableKeyword	String	Uncontrolled (Free-Text)	No	0..1

Example Mapping

ECHO 10

<ScienceKeyword>
  <CategoryKeyword>EARTH SCIENCE</CategoryKeyword> 
  <TopicKeyword>BIOSPHERE</TopicKeyword> 
  <TermKeyword>VEGETATION</TermKeyword> 
  <VariableLevel1Keyword>
    <Value>VEGETATION INDEX</Value>
      <VariableLevel2Keyword>
        <Value>NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)</Value>
      </VariableLevel2Keyword>
  </VariableLevel1Keyword>
  <DetailedVariableKeyword>0.9 DENSITY</DetailedVariableKeyword>
</ScienceKeyword>
<ScienceKeyword>
  <CategoryKeyword>EARTH SCIENCE</CategoryKeyword> 
  <TopicKeyword>BIOSPHERE</TopicKeyword> 
  <TermKeyword>VEGETATION</TermKeyword> 
  <VariableLevel1Keyword>
    <Value>EVERGREEN VEGETATION</Value>
  </VariableLevel1Keyword>
</ScienceKeyword>

UMM

ScienceKeywords: [
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "VEGETATION INDEX"
    VariableLevel2: "NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)"
    DetailedVariable: "0.9 DENSITY"
  },
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "EVERGREEN VEGETATION"
  }
],

ISO 19115-2 MENDS

ISO 19115-2 MENDS

An unlimited amount of science keywords may be listed (Cardinality: 1..*)

Specification

Path

Type

Notes

ISO 19115-2 MENDS

/gmi:MI_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords/gmd:MD_Keywords/ gmd:keyword/gco:CharacterString (list each value of the keyword hierarchy delimited by > )

String

KMS controlled. This is where the entire keyword hierarchy should be listed. Each keyword in the hierarchy must be separated by ">". If any keyword is missing and there exists a keyword later in the hierarchy (such as DetailedLocation), use NONE to fill in the values in between. The CMR will not translate the NONE values they are only used to place each keyword in its correct space in the hierarchy.

/gmi:MI_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords/gmd:MD_Keywords/ gmd:keyword/gmd:type/MD_KeywordTypeCode[@codeListValue="theme"]

Codelist

codeList=https://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml #MD_KeywordTypeCode

Select the value "theme" from the codelist. This codelist value does not directly map to a UMM element - choosing 'theme' indicates to CMR that the Science Keywords should be mapped.

Example Mapping

ISO 19115-2 MENDS

...
<gmd:identificationInfo>
  <gmd:MD_DataIdentification>
    <gmd:descriptiveKeywords>
      <gmd:MD_Keywords>
        <gmd:keyword>
          <gco:CharacterString>EARTH SCIENCE&gt;BIOSPHERE&gt;VEGETATION&gt;VEGETATION INDEX&gt;NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)&gt;NONE&gt;0.9 DENSITY</CharacterString>
        </gmd:keyword>
        <gmd:keyword>
          <gco:CharacterString>EARTH SCIENCE&gt;BIOSPHERE&gt;VEGETATION&gt;EVERGREEN VEGETATION</CharacterString>
        </gmd:keyword>
        <gmd:type>
          <gmd:MD_KeywordTypeCode codeList="https://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="theme">theme</gmd:MD_KeywordTypeCode>
        </gmd:type>
      </gmd:MD_Keywords> 
    </gmd:descriptiveKeywords>
  </gmd:MD_DataIdentification>
</gmd:identificationInfo>
...

UMM

ScienceKeywords: [
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "VEGETATION INDEX"
    VariableLevel2: "NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)"
    DetailedVariable: "0.9 DENSITY"
  },
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "EVERGREEN VEGETATION"
  }
],

ISO 19115-2 SMAP

ISO 19115-2 SMAP

An unlimited amount of science keywords may be listed (Cardinality: 1..*)

Specification

Path

Type

Notes

ISO 19115-2 SMAP

/gmd:DS_Series/gmd:seriesMetadata/gmi:MI_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords/ gmd:MD_Keywords/gmd:keyword/gco:CharacterString (list each value of the keyword hierarchy delimited by > )

String

KMS controlled. This is where the entire keyword hierarchy should be listed. Each keyword in the hierarchy must be separated by ">". If any keyword is missing and there exists a keyword later in the hierarchy (such as DetailedLocation), use NONE to fill in the values in between. The CMR will not translate the NONE values they are only used to place each keyword in its correct space in the hierarchy.

ISO 19115-2 SMAP

/gmi:MI_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:descriptiveKeywords/gmd:MD_Keywords/gmd:keyword/ gmd:type/MD_KeywordTypeCode[@codeListValue="theme"]

Codelist

codeList=https://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml #MD_KeywordTypeCode

Select the value "theme" from the codelist. This codelist value does not directly map to a UMM element - choosing 'theme' indicates to CMR that the Science Keywords should be mapped.

Example Mapping

ISO 19115-2 SMAP

...
<gmd:identificationInfo>
  <gmd:MD_DataIdentification>
    <gmd:descriptiveKeywords>
      <gmd:MD_Keywords>
        <gmd:keyword>
          <gco:CharacterString>EARTH SCIENCE&gt;BIOSPHERE&gt;VEGETATION&gt;VEGETATION INDEX&gt;NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)&gt;NONE&gt;0.9 DENSITY</CharacterString>
        </gmd:keyword>
        <gmd:keyword>
          <gco:CharacterString>EARTH SCIENCE&gt;BIOSPHERE&gt;VEGETATION&gt;EVERGREEN VEGETATION</CharacterString>
        </gmd:keyword>
        <gmd:type>
          <gmd:MD_KeywordTypeCode codeList="https://cdn.earthdata.nasa.gov/iso/resources/Codelist/gmxCodelists.xml#MD_KeywordTypeCode" codeListValue="theme">theme</gmd:MD_KeywordTypeCode>
        </gmd:type>
      </gmd:MD_Keywords> 
    </gmd:descriptiveKeywords>
  </gmd:MD_DataIdentification>
</gmd:identificationInfo>
...

UMM

ScienceKeywords: [
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "VEGETATION INDEX"
    VariableLevel2: "NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)"
    DetailedVariable: "0.9 DENSITY"
  },
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "EVERGREEN VEGETATION"
  }
],

UMM Migration

None

Future Mappings

ISO 19115-1

ISO 19115-1

Specification

Path

Type

Notes

ISO 19115-1

/mdb:MD_Metadata/mdb:identificationInfo/mri:MD_DataIdentification/mri:descriptiveKeywords/

mri:MD_Keywords/mri:keyword/gco:CharacterString

(list each value of the keyword hierarchy delimited by > )

String

KMS controlled. This is where the entire keyword hierarchy should be listed. Each keyword in the hierarchy must be separated by ">". If any keyword is missing and there exists a keyword later in the hierarchy (such as DetailedLocation), use NONE to fill in the values in between. The CMR will not translate the NONE values they are only used to place each keyword in its correct space in the hierarchy.

ISO 19115-1

/mdb:MD_Metadata/mdb:identificationInfo/mri:MD_DataIdentification/mri:descriptiveKeywords/

mri:MD_Keywords/mri:keyword/mri:type/mri:MD_KeywordTypeCode[@codeListValue="theme"]

Codelist

codeList=http://standards.iso.org/iso/19115/resources/Codelist/cat/codelists.xml#MD_KeywordTypeCode

Select the value "theme" from the codelist. This codelist value does not directly map to a UMM element - choosing 'theme' indicates to CMR that the Science Keywords should be mapped.

ISO 19115-1

...    
    <mdb:identificationInfo>
        <mri:MD_DataIdentification>

            <mri:descriptiveKeywords>
                <mri:MD_Keywords>
                    <mri:keyword>
                        <gco:CharacterString>EARTH SCIENCE&gt;BIOSPHERE&gt;VEGETATION&gt;VEGETATION INDEX&gt;NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)&gt;NONE&gt;0.9 DENSITY</gco:CharacterString>
                    </mri:keyword>
                    <mri:keyword>
                        <gco:CharacterString>EARTH SCIENCE&gt;BIOSPHERE&gt;VEGETATION&gt;EVERGREEN VEGETATION</gco:CharacterString>
                    </mri:keyword>
                    <mri:type>
                        <mri:MD_KeywordTypeCode
                            codeList="http://standards.iso.org/iso/19115/resources/Codelist/cat/codelists.xml#MD_KeywordTypeCode"
                            codeListValue="MD_KeywordTypeCode_theme">theme</mri:MD_KeywordTypeCode>
                    </mri:type>
                </mri:MD_Keywords>
            </mri:descriptiveKeywords>
         </mri:MD_DataIdentification>
    </mdb:identificationInfo>       
...

UMM

ScienceKeywords: [
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "VEGETATION INDEX"
    VariableLevel2: "NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)"
    DetailedVariable: "0.9 DENSITY"
  },
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "EVERGREEN VEGETATION"
  }
],

History

UMM Versioning

Version	Date	What Changed
1.0.0		Initial Release

ARC Documentation

Version	Date	What Changed	Author
1.0	5/4/18	Recommendations/priority matrix transferred from internal ARC documentation to wiki space	Jeanne' le Roux

Page tree

Science Keywords

Element Description

Best Practices

Element Specification

ARC Priority Matrix

Dialect Mappings

UMM Migration

Future Mappings

History

UMM Versioning

ARC Documentation