GIS Local Web Viewer

An offline-first GIS web application for visualizing, exploring, and querying geospatial field data locally — no internet or cloud dependency required.

Built with FastAPI, GeoPandas, and Leaflet.js.

⚠️ This project is a work in progress. Core features are functional; some enhancements are still in development.

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Overview

GIS Local Web Viewer converts GIS data files — GeoJSON, Shapefile, and File Geodatabase (.gdb) — into an interactive web map. It's designed for humanitarian field data workflows where an internet connection can't be relied on: everything runs on localhost.

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Features

• Multi-format support: GeoJSON, Shapefile (with automatic handling of the .dbf 10-byte field name limit), and File Geodatabase (.gdb) via pyogrio/OpenFileGDB.
• Automatic layer discovery: drop a folder into data_layers/ and it's auto-loaded as a layer — no manual configuration.
• Offline raster basemaps: any XYZ tile folder placed in raster_data/ is auto-detected (zoom levels, tile extension) and made switchable from the map's layer control.
• Mixed geometry handling: tables containing both spatial and non-spatial rows (common in real-world .gdb exports) are automatically split into separate spatial/table layers.
• Attribute search:
  • General spatial search (press Enter → highlights match, pans map, opens popup)
  • Live-filtering search by name / ID / camp
  • Family-name search (matches the last word of a person's full name)
• Interactive field mapping: map arbitrary column names (person name, ID, camp) per table layer directly from the sidebar, with auto-detected defaults.
• Table ↔ spatial linking: clicking a person record opens a query panel and pans the map to their linked location.
• Clear error handling: layers or basemaps that fail to load (unsupported raster format, corrupt file, etc.) show a dismissable error banner instead of failing silently.

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Tech Stack

Backend: Python, FastAPI, Uvicorn, GeoPandas, pyogrio, Shapely, Pydantic

Frontend: HTML, CSS, JavaScript (Vanilla), Leaflet.js

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Project Structure

GIS-Local-Web-Viewer/
├── backend/              # FastAPI app: adapters, routes, models
├── frontend/             # Leaflet map UI (HTML/CSS/JS)
├── services/             # Helper services
├── data_layers/          # GIS layers, auto-loaded (each subfolder = one layer)
├── raster_data/          # Offline basemap tiles, auto-loaded (each subfolder = one basemap)
├── uploads/              # Files uploaded manually via the UI
└── requirements.txt

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Running Locally

# Create and activate a virtual environment
python -m venv venv
venv\Scripts\activate      # Windows

# Install dependencies
pip install -r requirements.txt

# Run the server
uvicorn backend.main:app --reload

Then open your browser at: http://127.0.0.1:8000

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Screenshots

Coming soon.

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Version 1 Scope & Limitations

By design, this version does not include:

• User authentication / accounts
• A database (PostgreSQL/PostGIS)
• WebSocket connections or real-time sync
• Drawing or feature-editing tools
• Network/multi-user deployment (local, single-user only)

See GIS_SPEC.md for the full Version 1 specification.

Roadmap

• Fix cross-table name matching for spatial linking
• Persistent field-mapping configuration (currently session-only)
• Real-time polling for data_layers/ updates
• Offline street basemap tiles
• Broader multi-layer search

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Note

This is a volunteer project supporting humanitarian field teams. This repository does not contain any real personal data.

License

Not yet determined.