Platform

Element Description

The platform elements enable the specification of platforms used to collect the data available in the dataset. Platforms provided in CMR metadata must be chosen from a controlled keyword hierarchy maintained in the Keyword Management System (KMS). A list of valid platform keywords can be found here: https://gcmdservices.gsfc.nasa.gov/static/kms/platforms/platforms.csv?

Optionally, attributes specific to the platform (such as equator crossing time, inclination angle, orbital period, etc.) may be specified in the characteristics elements.

Best Practices

Platform keywords are important for the discovery of data. All relevant platforms should be listed for each dataset. It is preferred that more specific platform keyword terms be chosen from the KMS when available. For example, if data were collected from the NASA DC-8 aircraft, it is preferred that "NASA DC-8" be listed as the platform as opposed to the more generic "AIRCRAFT" keyword. If a particular platform 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.

In the KMS, there is a hierarchy for platform keywords. Platform keywords should be provided in the metadata field corresponding to the appropriate position of the keyword hierarchy, otherwise the keyword will be rendered invalid. For example, the platform short name specified in the KMS should not be provided in the platform 'long name' field in the metadata. When listing platforms a platform short name will always be required. While platform long names are not required, it is highly encouraged that long names be provided if one is listed in the KMS. Many platform short names are comprised of acronyms, so inclusion of the long name provides additional context to a user who may not be familiar with the acronym. Platform keywords are not case sensitive.

It is recommended that platform keywords be assigned in a consistent manner. For example, if data for several collections were collected by the "LANDSAT-8" satellite, it is recommended that the metadata for all of those collections list "LANDSAT-8" as the platform short name. Providing "LANDSAT-8" as the platform in some records, but the more generic "LANDSAT" as the platform in other records, results in an inconsistent experience for a user discovering data. This is especially true for users narrowing down their search results in the Earthdata Search client by using the faceted search options.

Examples:

Terra > Earth Observing System, Terra (AM-1)

METOP-A > Meteorological Operational Satellite - A

VIC-LSM > Variable Infiltration Capacity (VIC) Land Surface Model

MESONET > Mesoscale Meteorological Network

BE-200 > Beechcraft King Air BE-200

Element Specification

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

Providing platform characteristics is optional. An unlimited amount of platform characteristics may be specified for a particular platform (Cardinality: 0..*). If platform characteristics are provided, all 5 sub-fields (Name, Description, DataType, Unit, Value) are required.

Model	Element	Type	Usable Valid Values	Constraints	Required?	Cardinality
UMM-Common	Platform/Type	String	Platform Category Keywords	KMS controlled	No	0..1
UMM-Common	Platform/ShortName	String	Platform Short_Name Keywords	KMS controlled	Yes	1
UMM-Common	Platform/LongName	String	Platform Long_Name Keywords	KMS controlled	No	0..1
UMM-Common	Platform/Characteristics/Name	String	n/a	Minimum # characters: 1 Maximum # characters: 80	Yes	1
UMM-Common	Platform/Characteristics/Description	String	n/a	Minimum # characters: 1 Maximum # characters: 2048	Yes	1
UMM-Common	Platform/Characteristics/DataType	Enumeration	STRING FLOAT INT BOOLEAN DATE TIME DATETIME DATE_STRING TIME_STRING DATETIME_STRING	n/a	Yes	1
UMM-Common	Platform/Characteristics/Unit	String	n/a	Minimum # characters: 1 Maximum # characters: 20	Yes	1
UMM-Common	Platform/Characteristics/Value	String	n/a	Minimum # characters: 1 Maximum # characters: 80	Yes	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>
</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)"
  },
  {
    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>
</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)"
  },
  {
    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 ">"

/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)</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)"
  },
  {
    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 ">"

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

UMM

ScienceKeywords: [
  {
    Category: "EARTH SCIENCE",
    Topic: "BIOSPHERE",
    Term: "VEGETATION",
    VariableLevel1: "VEGETATION INDEX"
    VariableLevel2: "NORMALIZED DIFFERENCE VEGETATION INDEX (NDVI)"
  },
  {
    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		String

ISO 19115-1

UMM

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

Platform

Element Description

Best Practices

Element Specification

ARC Priority Matrix

Dialect Mappings

UMM Migration

Future Mappings

History

UMM Versioning

ARC Documentation