ECS MetadataConsiderations for Preservation

SiriJodha S. KhalsaNational Snow and Ice Data Center

A Little History

ECS = NASA's Earth Observing System (EOS) Data and Information System (EOSDIS) Core System

Data model based on FGDC Content Standard for Digital Geospatial Metadata

CSDGM became basis of ISO 19115 ECS data model became basis of RS

extension to FGDC which was used in 19115-2

The ECS Metadata Model

Bounded set of attributes (287 originally) intended to cover essential characteristics of all earth science data sets

Granule-level (inventory) and Collection (catalog/discovery) metadata

ECS Metadata Types

In addition: Archival Metadata: Product-specific

metadata that accompanies the granule when it is delivered to the data users, but need not be searchable by the system.

Structural Metadata: describes the specific data structures within the granule, including information necessary for geolocation of the data. Only in Data Product

Subsystem Persistent Metadata: Metadata generated by each subsystem to help identify, process and track objects in the system

Metadata provides information to: Identify (title, origin, contents) Locate (position, date & time) Interpret (descriptions, units & scaling factors,

accuracy) Document (software version, production history,

ancillary inputs)

Production System (as originally planned)

SCF

DataData

ProductGeneration

MetadataMetadata

ECS

AncillaryData

AncillaryData

Collection and Granule,AutoQA, PH

ESDT

Production System (as it evolved)

SIPS

DataData

IngestMetadataMetadata

ECS

AncillaryData

AncillaryData

ESDT

ESDT

Location of Metadata

ECS Databases Ingest, data pool, archive, etc.

HDF-EOS Data Files Distributed metadata files Online documentation (DAACs, Instrument

Team & Product Team Websites)

Issues

DAACs will not alter original files (and therefore the metadata they contain)

QA updates only in distributed metadata, so metadata can get out of sync

Metadata spread across several different ECS databases, DAAC websites, the product itself

How gather for preservation?