[SIS-418] Global Change Master Directory (GCMD) keywords in netCDF

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.3, 0.4, 0.5, 0.6, 0.7, 0.8
• Component/s: Storage
• Assignee: Unassigned
• Reporter: Martin Desruisseaux
• Created: 21/May/18 09:16
• Updated: 14/Nov/18 13:12

Description

The keywords attribute in netCDF files sometime contains a value like below:

:keywords = "EARTH SCIENCE > Oceans > Ocean Temperature > Sea Surface Temperature" ;
:keywords_vocabulary = "GCMD Science Keywords" ;

Currently, NetcdfMetadata store the whole string in a single ISO 19115 Keyword value, while actually it should be many keywords. The GCMD keywords structure is described on the NASA Global Change Master Directory (GCMD) Keywords web page. It uses the following hierarchical structure:

Category > Topic > Term > Variable > Detailed Variable

We may interpret the structure as below:

• We support only "EARTH_SCIENCE" (other possible values are "CONTINENT", "Earth Remote Sensing Instruments", etc.)
• KeywordType.DISCIPLINE (note: would be wrong if above was "CONTINENT" for example).
• KeywordType.THEME (note: would be KeywordType.INSTRUMENT instead if above was "Earth Remote Sensing Instruments" instead than "Earth Science").
• KeywordType.SUB_TOPIC_CATEGORY

We may also provide a KeywordClass with a reference to GCMD as an ontology.

Issue Links

• is related to: SIS-356 NetCDF reader should recognize Earth Observation metadata
• relates to: SIS-361 NetCDF to ISO 19115:2014 mapping