Thanks for information from a geoviz perspective!! In the accompanying demo app (example/geo-viewer), we are using LeafletJS for the terrain area selection UI

Thanks for information from a geoviz perspective!! In the accompanying demo app (example/geo-viewer), we are using LeafletJS for the terrain area selection UI and also for displaying a moving camera (which can also be regarded as a drone ;)) in the global geo coordinate system. We found Leaflet is so valuable. Really excited to know about OpenLayers. We plan to spin off example/geo-viewer as the base of a new standalone 3D GIS app (which is also OSS). In this new app, we want to implement/accumulate common GIS features and push the limit of browser-based GIS applications. OpenLayers seems perfect for an abstraction module for tile fetching, layer interactions, etc. It looks so matured and supporting so many tile layer service providers.