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Geospatial Metadata & Standards

Proper metadata is critical in geospatial science — without knowing a dataset's coordinate reference system, temporal extent, or spatial resolution, the data is effectively unusable. Several well-established standards govern how geospatial metadata is created and shared.

Core Metadata Standards​

ISO 19115 / ISO 19139​

The international standard for geographic information metadata. ISO 19115 defines the schema; ISO 19139 provides the XML encoding.

  • Use: Official metadata records, data portals, INSPIRE compliance
  • Key fields: Title, abstract, spatial extent, temporal extent, CRS, lineage, contact information
  • Spec: ISO 19115

INSPIRE Metadata​

The European Union's spatial data infrastructure directive requires metadata conforming to ISO 19115 with additional INSPIRE-specific requirements.

Dublin Core (with spatial extensions)​

A general-purpose metadata standard that can be extended with geospatial elements (coverage, spatial).

  • Use: Simple metadata for data catalogs and repositories
  • Spec: Dublin Core

STAC (SpatioTemporal Asset Catalog)​

A modern, JSON-based metadata specification designed for Earth observation data. Describes spatiotemporal assets with standardized fields and extensions.

  • Use: Satellite data catalogs, cloud-native data discovery
  • Key fields: Bounding box, datetime, assets (links to data files), properties
  • Spec: STAC Spec

Coordinate Reference Systems (CRS)​

Understanding CRS is fundamental to all geospatial work:

  • WGS 84 (EPSG:4326) — The most common geographic CRS (latitude/longitude), used by GPS
  • UTM Zones (EPSG:326xx) — Projected CRS for metric measurements, divided into 60 zones globally
  • ETRS89 (EPSG:4258) — European Terrestrial Reference System, standard for European data
  • Web Mercator (EPSG:3857) — Used by web maps (Google Maps, OpenStreetMap), distorts area

Best practice: Always document the CRS (as an EPSG code) in your metadata. Use projected CRS (e.g., UTM) for area/distance calculations, and geographic CRS (e.g., WGS 84) for data exchange.

  • Lookup tool: EPSG.io — Search and convert CRS codes

Ontologies and Vocabularies​

CF Conventions (Climate and Forecast)​

Standard names and units for climate and forecast data, used with NetCDF files.

GEMET (General Multilingual Environmental Thesaurus)​

A controlled vocabulary for environmental topics, used in INSPIRE metadata.

GCMD Keywords (NASA)​

Hierarchical keywords for Earth science data discovery.

Best Practices​

  1. Always include CRS information — Either embedded in the file (GeoTIFF) or documented in metadata
  2. Document spatial and temporal extent — Bounding box, date range, temporal resolution
  3. Specify data lineage — Processing chain from raw data to analysis-ready products
  4. Use standard vocabularies — CF Conventions for climate data, GCMD keywords for discovery
  5. Provide data quality information — Accuracy, completeness, positional uncertainty