EO Glossary

The Community Thesaurus for Earth Observation Sciences — maintained by CEOS & EC KCEO.

Vocabulary companion to the CEOS Interoperability Handbook 2.0. Term structure, classification, and governance follow:

Strobl, P. A., Woolliams, E. R., & Molch, K. (2024). Lost in Translation: The Need for Common Vocabularies and an Interoperable Thesaurus in Earth Observation Sciences. Surveys in Geophysics. DOI: 10.1007/s10712-024-09854-8

Note: This glossary is currently at an early stage and still work in progress. It is not 100% reviewed yet and some things might change over time. Stay tuned on GitHub or reach out to us!

Local Development

Built with Docusaurus 3.9.2. Requires Node.js ≥ 18 and uv (Python package manager, used for export scripts).

# Clone and install
git clone https://github.com/ceos-org/eo-glossary.git
cd eo-glossary
npm install

# Start dev server (hot reload)
# Also runs Python export scripts before starting (requires uv)
npm start

# Production build
# Also runs Python export scripts before building (requires uv)
npm run build

# Serve the production build locally
npm run serve

The dev server runs at http://localhost:3000/eo-glossary/ by default.

If uv is not installed, the Python export scripts are skipped gracefully and npm start / npm run build still work normally.

Project Structure

eo-glossary/
├── docs/
│   ├── terms/              ← one .md file per term
│   ├── assets/             ← images and logos
│   ├── _template.md        ← term template (copy to add new terms)
│   ├── introduction.md
│   ├── concepts.md
│   ├── contribute.md
│   ├── dependency-graph.md
│   ├── changelog.md
│   └── impressum.md
├── plugins/
│   ├── remark-glossary-links.mjs           ← auto cross-referencing (build-time)
│   └── docusaurus-plugin-glossary-links.mjs
├── scripts/
│   ├── export_glossary.py                  ← exports to JSON/XLSX/Parquet
│   └── generate_sigma_graph_data.py        ← dependency graph data
├── src/
│   ├── css/custom.css      ← design system (dark-mode-first)
│   └── pages/index.tsx     ← custom homepage
├── static/                 ← static assets served at root
│   ├── llms.txt            ← AI crawler guidance (llmstxt.org standard)
│   └── llms-full.txt       ← all term definitions as plain Markdown (generated at build time)
├── mcp/
│   └── server.js           ← MCP server for AI assistant integration
├── sidebars.ts             ← sidebar navigation config
└── docusaurus.config.ts    ← main Docusaurus config

Contributing

See docs/contribute.md for the full guide. Quick reference below.

Editing an existing term

Click the Edit this page link at the bottom of any term page — it opens the file directly on GitHub.

Adding a new term

1. Copy docs/_template.md to docs/terms/your_term_name.md (lowercase, underscores).
2. Fill in the frontmatter and definition following the template.
3. Open a PR — the sidebar and term count update automatically. CI will build, generate exports, and deploy.

Term file format

---
title: Your Term
description: "One-sentence substitutable definition (used for SEO and link previews)."
tags:
  - core            # term class: base | core | controversial | high-impact
  - to be discussed # status: to be defined | to be discussed | to be approved | approved
---

# Your Term

## 1 Definition

Substitutable definition — must NOT start with "Your Term is...".
Write it so it can directly replace the term in a sentence.

### Notes

- Additional context or clarifications.

### Examples

- Concrete example.

### Sources

- Author et al. Year — or [Source](https://example.com)

Do not add cross-links manually. The build system automatically links term mentions in the Definition and Notes sections to their glossary pages. Source files must remain plain Markdown.

Tag system

Tag	Meaning
base	Foundational ontology — usable across all sciences
core	Standard EO vocabulary with broadly agreed definitions
controversial	Contested definitions across communities; multiple definitions provided
high-impact	Concepts requiring full framework documents, not a single sentence

Status tag	Meaning
to be defined	Placeholder; definition not yet written
to be discussed	Draft exists; community discussion needed
to be approved	Definition ready; awaiting formal approval
approved	Definition approved by the community

Definition quality rule (THES#4 — substitution principle)

Every definition must be directly substitutable for the term in a sentence:

• Wrong: "Accuracy is the proximity of measurement results to the accepted value."
• Correct: "Proximity of measurement results to the accepted value."

Cross-referencing

Term cross-references are resolved automatically at build time by a Remark plugin (plugins/remark-glossary-links.mjs). It scans all term files, builds a term→URL map, and linkifies matching term mentions in the Definition and Notes sections only — without ever modifying source files. Examples and Sources sections are intentionally excluded.

Longest-match wins: "Earth Observation" is linked as a single term, not as "Earth" + "Observation" separately.

Exports

Automated exports (JSON, XLSX, Parquet) are generated on every push and available in exports/.

Query terms via DuckDB without downloading the full dataset:

INSTALL httpfs;
LOAD httpfs;

SELECT *
FROM read_parquet('https://github.com/ceos-org/eo-glossary/raw/refs/heads/main/exports/parquet/terms_definition_1.parquet')
WHERE term ILIKE 'climate projection';

Run with duckdb -ui or any DuckDB client.

AI Access

The glossary is designed to be AI-ready. All access patterns are described in static/llms.txt (served at /llms.txt, following the llmstxt.org standard).

Resource	URL	Format	Use case
AI guidance	/llms.txt	Markdown	LLM crawlers and agents
All definitions (plain text)	/llms-full.txt	Markdown	Direct LLM ingestion, RAG chunking
All definitions (structured)	exports/json/terms.json	JSON	RAG pipelines, programmatic access
All definitions (columnar)	exports/parquet/	Parquet	DuckDB, data science
Per-term pages	/terms/{slug}	HTML + JSON-LD	Web crawlers, semantic search
Sitemap	/sitemap.xml	XML	Crawlers
RSS	/rss.xml	RSS 2.0	Feed readers

Each term page includes Schema.org DefinedTerm JSON-LD structured data.

MCP Server (AI assistant integration)

The mcp/ directory contains a Model Context Protocol server that lets AI assistants (Claude Desktop, etc.) query the glossary interactively.

cd mcp && npm install

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "eo-glossary": {
      "command": "node",
      "args": ["/path/to/eo-glossary/mcp/server.js"]
    }
  }
}

Available tools: list_terms(tag?), get_term(term), search_terms(query).

CI/CD

GitHub Actions (.github/workflows/ci.yml) runs on every push to main:

1. Runs Python export scripts (export_glossary.py, generate_sigma_graph_data.py) via uv
2. Commits generated exports and graph data back to main
3. Installs Node dependencies and builds the Docusaurus site
4. Deploys to GitHub Pages (gh-pages branch)