Three.js is a very promising tool if you want to add a third dimension to your web maps.
How to create a WebGL Earth with three.js
New Zealand is the perfect country to map, as an isolated country surrounded by a vast ocean with tons of free data available.
Map projections applied to photographs.
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Using Leaflet for high-resolution zoomable images.
Synchronize two or more maps or images with Leaflet.
Research paper and Tech Talk at Googleplex.