Geocontext

🚀 geocontext

An experimental MCP server providing spatial context for LLMs.

🚀 Quick Start

Usage of the Published Version

For example, with "Cursor Settings / MCP / Add server":

{
  "mcpServers": {
    "geocontext": {
      "command": "npx",
      "args": ["-y", "@ignfab/geocontext"]
    }
  }
}

Usage with Docker

docker compose build
docker compose up -d

Then:

{
  "mcpServers": {
    "geocontext": {
      "url": "http://localhost:3000/mcp"
    }
  }
}

✨ Features

Using Spatial Services

Some services from the Geoplateforme:

• geocode(text) relies on the Geoplateforme's autocomplete service to convert a place name to a position (lon, lat).

Ex: What is the position (lon, lat) of the town hall of Vincennes?

• altitude(lon, lat) relies on the Geoplateforme's altimetric calculation service to convert a position to an altitude.

Ex: What is the altitude of the town hall of Loray (25)?

Searching for Information about a Place

The idea here is to answer specific questions by processing server - side calls to the Geoplateforme's WFS services:

• adminexpress(lon, lat) allows you to retrieve administrative information (municipality, department, region, ...) for a given place by its position.

Ex: What are the administrative information for the town hall of Vincennes?

• cadastre(lon, lat) allows you to retrieve cadastral information (parcel, sheet, ...).

Ex: What are the cadastral information for the town hall of Vincennes?

• urbanisme(lon, lat) allows you to retrieve urban planning information (PLU, POS, CC, PSMV).

Ex: What is the current PLU document for the port of Marseille?

• assiette_sup(lon, lat) allows you to retrieve Public Utility Servitudes (SUP).

Exploring Vector Data

Exploring Tables

• gpf_wfs_list_types() to list the available tables on the Geoplateforme's WFS (GetCapabilities) - deprecated (too many results)
• gpf_wfs_search_types(keywords, max_results = 10) to search for the available tables on the Geoplateforme's WFS (GetCapabilities)

• What are the available ADMINEXPRESS vintages on the Geoplateforme?
• Which BDTOPO table corresponds to buildings?
• In which BDTOPO table can we find bridges?

Exploring Table Structures

• gpf_wfs_describe_type(typename) to retrieve the schema of a table (DescribeFeatureType)

• What information is available for municipalities with ADMINEXPRESS - COG.LATEST?
• Compare the municipality model between ADMINEXPRESS - COG:2024 and ADMINEXPRESS - COG.LATEST

Exploring Table Data

• gpf_wfs_get_features(typename, ...) to retrieve the data of a table (GetFeature)

• What are the 5 most populous municipalities in the Doubs (25)?
• How many buildings are there within 5 km of the Eiffel Tower?

📦 Installation

Building the Local Version

git clone https://github.com/ignfab/geocontext
cd geocontext
npm install
npm run build

Using the Local Version

{
  "mcpServers": {
    "mcp-helloworld": {
      "command": "node",
      "args": ["/absolute/path/to/geocontext/dist/index.js"]
    }
  }
}

Debugging the Local Version

npx -y @modelcontextprotocol/inspector node dist/index.js

📚 Documentation

Motivation

LLMs reinforce the idea that magic is possible with computing. But it's not. For an assistant to know the date and time, for example, it needs to be interfaced with a MCP time. Similarly, for it to read a page, it needs to be interfaced with a MCP fetch.

In terms of geographical data, if a user asks a question implying that the assistant should be able to know the position of an address, there is a good chance that the answer will be plausible but false.

Although it is technically possible to connect REST/GeoJSON APIs such as APICARTO, their design is not suitable (5000 results by default, large geometries in responses, complex geometries to provide, ...).

The idea here is to experiment with the design of an MCP that makes the data and services of the Geoplateforme accessible to an LLM.

Design Principles

• Do not copy the Geoplateforme's data (goal: identify possible improvements to the services rather than duplicate them).
• Minimize the size of responses (goal: optimize the number of tokens, avoid hallucinations, be able to use local models).
• ...

Precautions

• This development is a POC in incubation with IgnFab (archiving of mborne/geocontext is in progress).
• If it proves useful to industrialize it, the repository will be migrated under the responsibility of IGN and the tool will be renamed (e.g., IGNF/mcp-gpf-server).
• Several possible problems and improvements have been identified and are being mitigated/resolved (see issues).
• This tool is not magic (see Features to get an idea of its capabilities).

Configuration

For advanced use:

Contribution

Issues and Feature Requests

Don't hesitate to create an issue if you encounter a problem! Please provide:

• The assistant and the model used.
• The request you make to the assistant (e.g., "How many bridges cross the Seine?")

Proposing a New Feature

Don't hesitate:

• Fork the repository.
• Create a new tool.
• Test it on your side.
• Make a pull - request.

Credits

• mcp-framework provides the development framework for the MCP:

# For example, to expose the list of WMTS layers
mcp add tool gpf_wmts_layers

• @camptocamp/ogc-client for reading XML responses from WFS, WMTS, ... services.
• MiniSearch for keyword search.
• jsts for geometric processing (e.g., sorting responses by distance to the searched point).

📄 License

MIT