Allmaps Leaflet plugin (Leaflet#9390)

docs/_plugins/basemap-formats/allmaps-leaflet.md

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+---
+name: allmaps-leaflet
+category: basemap-formats
+repo: https://github.com/allmaps/allmaps/tree/main/packages/leaflet
+author: Allmaps
+author-url: https://www.allmaps.org
+demo: https://observablehq.com/@allmaps/leaflet-plugin
+compatible-v0:
+compatible-v1: true
+---
+
+Allmaps plugin for Leaflet. This plugin allows displaying georeferenced [IIIF](https://iiif.io/) images on a Leaflet map. 100,000s of (historical) maps are available through IIIF, across libraries, archives and museums worldwide. The plugin works by loading [Georeference Annotations](https://preview.iiif.io/api/georef/extension/georef/) and uses WebGL to transform images from a IIIF image server to overlay them on their correct geographical position. See [allmaps.org](https://www.allmaps.org) for more information.