A site that lets you create map layers on top of Open Streetmap and make them shareable and embeddable. You can upload geodata or sketch in the data you want.
Source code: https://github.com/umap-project/umap
A Python module that lets you take data and easily generate a Leaflet map of it. Defaults to Open Streetmap but can also use Stamen Terrain and Toner, Mapbox Bright and Control Room. Can use custom tilesets if you have the appropriate API key. You can output the map to local storage. If you can define a map some other way, you can do the same with Folium (probably more easily). Polygons can be drawn on the map as you'd expect.
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