1. Variables @ NASA GESDISC
Mahabal Hegde
ADNET Systems/NASA GESDISC

2. How are they exposed?
Subsetting Services
Examples: Mirador, Simple Subset Wizard
Visualization Services
Examples: GIOVANNI, OGC Services

3. Variables in GIOVANNI
Attributes

4. Variables in GIOVANNI
Facets (Attributes)

5. Variables in GIOVANNI
Keywords

6. Variables in GIOVANNI
Names, Units, Resolutions, Color Palettes, Data range

7. Variable Attributes: Examples
Keywords
Examples: Land-only, Unfrozen
Disciplines
Examples: Hydrology, Aerosols
Resolutions (Spatial + Temporal)
Examples: Monthly, 1°

8. Variable Attributes: Examples
Source
Examples: AIRS, GPM
Measurements
Examples: Air Temperature, Soil Moisture

9. Variable Attributes: Examples
Color Palettes
Example:
<sld
url=”net_radiation_sld.xml"
label="Blue-Yellow-Red (Div), 65” />

10. Variable Attributes: Examples
Discovery Methods
Example:
osdd=“

11. Variable Catalog Curation
Editor
OPeNDAP
Apache
Solr
CMR
GCMD or DIF Document
Data Archive
GIOVANNI

12. Sources of Variable Information
Attributes
Collection Metadata
Spatial coverage
Platform/Instrument
Discovery method
Granule metadata
Temporal Coverage
Documentation +
Subject Matter Expertise
Spatial and temporal resolution
Units
Color palettes
Valid data range
Dimensions
Measurements
Disciplines
Sample granule & OPeNDAP URL

13. Variable Metadata: Challenges
Some attributes known only to domain experts.
Example:
Data range, Color palette, Measurement

14. Variable Metadata: Challenges
Metadata provider may not be aware of how it is consumed.
Example:
Long name

15. Variable Metadata: Challenges
Questionable quality when they exist.
Example:
Typos, Not so relevant keywords

16. Variable Metadata: Challenges
Incomplete metadata
Example:
Temporal information, Wavelength values

17. Variable Metadata: Challenges
Several standards or conventions to choose from.
Conventions are recommendations and are not mandatory.

18. Variable Metadata: Challenges
Tedious to curate: just do it.

19. Looking forward …
Variable based services in a single user interface
Data Lists (Predefined, User-defined)