Introduction
In the fields of digital archives and humanities research, there is a growing need to view historical maps, old photographs, and other materials within a geographic context. IIIF (International Image Interoperability Framework) is an international standard for enhancing image interoperability, and with the recent IIIF Georeference Extension, it is now possible to attach geographic coordinate information to IIIF images.
The IIIF Georeference Viewer (iiif_geo) is a web application for visualizing such georeferenced IIIF content on interactive maps.
What is the IIIF Georeference Extension?
The IIIF Georeference Extension is a specification for embedding geographic coordinate information in IIIF manifests and canvases. This makes it possible to accurately overlay IIIF images such as historical maps onto modern maps.
Previously, georeferencing historical maps required specialized GIS software. By leveraging this extension, users can now view and compare georeferenced content directly in a web browser.
Features
Dynamic URL Loading
You can load any IIIF manifest or GeoJSON file directly from a URL using query parameters. Try the demo below:
Demo: https://nakamura196.github.io/iiif_geo/
Supported Data Formats
- IIIF Manifest — IIIF Presentation API 3.0 manifests
- IIIF Canvas — Individual canvas objects
- Linked Places Format — A standard format for historical place name data
- GeoJSON — A widely used geographic data format
Interactive Map Display
The map display, powered by Leaflet and MapLibre GL, efficiently renders large numbers of point data with marker clustering. Multiple base maps are available, including aerial photography and various tile layers.
Split-Pane Layout
The viewer supports a split-pane layout with a map on the left and a deep-zoom IIIF image viewer (OpenSeadragon) on the right. This is particularly useful for comparing historical maps with modern maps side by side.
Deep Zoom
OpenSeadragon enables deep zoom into high-resolution images. Even large historical maps can be explored down to the finest detail.
Bilingual Support
The application provides a bilingual UI in Japanese and English, supporting international use.
Tech Stack
The tool is built with the following technologies:
| Technology | Purpose |
|---|---|
| Nuxt 4 / Vue 3 | Application framework |
| Leaflet | 2D tile map rendering |
| MapLibre GL | Vector tile map rendering |
| OpenSeadragon | IIIF image deep zoom |
| GitHub Pages | Hosting |
By using Nuxt 4’s static site generation (SSG) and deploying to GitHub Pages, there are no server-side operational costs.
Use Cases
Digital Humanities
- Historical map comparison: Overlay historical maps (e.g., Edo-period maps) with modern maps to visually trace urban transformation
- Geographic distribution of cultural heritage: Map museum and library collections via IIIF onto geographic views
- Fieldwork support: Browse historical map materials for survey areas directly in the browser
Libraries and Museums
Any institution with IIIF-compatible digital archives can use this viewer simply by specifying the URL of their map collections. A major advantage is the ability to add geographic visualization capabilities to existing IIIF content without developing custom systems.
How to Use
- Visit the demo site
- Specify a IIIF manifest URL or GeoJSON URL via query parameters
- Click markers on the map to browse content
- Use the split pane to compare IIIF images and maps side by side
The source code is available on GitHub.
Conclusion
The IIIF Georeference Viewer supports the IIIF Georeference Extension specification and provides an easy way to visualize historical maps and digital archive content on maps. By leveraging modern web technologies such as Nuxt 4, Leaflet, and OpenSeadragon, it delivers advanced geospatial visualization entirely within the browser. We hope it proves useful for research and education in the Digital Humanities.