Darwin Core, GBIF, and OBIS Reference Guide
Reference Guide: Darwin Core, the Unified GBIF Data Model, and OBIS
This guide explains how Darwin Core supports interoperability for Fisheries and Oceans Canada (DFO) salmon data, and how GBIF/OBIS publication models connect to that workflow.
What is Darwin Core?
Darwin Core (DwC) is a biodiversity data standard maintained by TDWG. It provides common terms for recording occurrences, events, measurements, and related metadata.
Darwin Core as an interoperability layer
In DFO Pacific science workflows, teams use different local schemas. Darwin Core acts as a translation layer so those local datasets can be aligned and shared without forcing one internal database design.
The Unified GBIF Data Model
The GBIF Unified Data Model extends DwC to support linked structures such as:
- Events
- Occurrences
- Measurements/Facts
This is useful for salmon workflows where one program may generate survey events, biological observations, and derived indicators.
OBIS context
OBIS applies Darwin Core patterns to marine biodiversity exchange, including marine-focused extensions and publication pathways.
DFO salmon semantic position
For salmon-specific semantics in this ecosystem:
- treat the DFO Salmon Ontology as canonical for term meaning and identifiers
- use Darwin Core terms for interoperability and publication packaging
- map outward to GBIF/OBIS as needed
Canonical ontology entry point:
Example field alignment
| DFO Field / Concept | Darwin Core Term | Notes |
|---|---|---|
Species_Code or Species_Name |
scientificName |
Resolve against accepted taxonomic services |
Sample_ID |
occurrenceID |
Use stable unique identifiers |
Catch_Date |
eventDate |
Prefer ISO 8601 |
Survey_Name |
eventID |
Use hierarchical event IDs where needed |
Latitude, Longitude |
decimalLatitude, decimalLongitude |
Use WGS84 |
Depth_m |
minimumDepthInMeters, maximumDepthInMeters |
Include both when possible |
| biological metrics | measurementType, measurementValue, measurementUnit |
Use controlled value strategy |
| method/protocol | samplingProtocol |
Keep method terms consistent |
Practical guidance
- start semantic mapping in DFO ontology terms
- map to DwC publication terms for external interoperability
- keep provenance explicit for transformations and crosswalks
Darwin Core is not your internal data model. It is your interoperability contract.