You can store in the markers any data that you need.

Online Maps does not have built-in clustering feature.
But you can implement it yourself, or use some prepared scripts. For example:
http://forum.infinity-code.com/viewtopi … 1809#p1809
http://infinity-code.com/atlas/online-m … ample.html

The current version of Online Maps does not support multiresolution maps. The entire map has the same resolution.

Yes, you can rotate the map.

The project is a Cardboard VR app for Android and iOS that allows users to flyby and explore a region of Italy called Lazio, that is the highlited zone in the screenshot. On this region there are some markers - an upper bound could be 1000 - that user can click to open 360 images of that specific location, so i should be able to retrieve some extra data from the markers, not just display the location label.

When markers are too close to be viewed from a certain distance they should be depicted as a cluster. When the user click a cluster, the camera would move closer until the cluster resolves in smaller clusters or markers. Of course, moving closer to the terrain should display higher resolution maps.

The multiresolution maps could only be used on the highlited region, while the rest of Italy can be a low resolution map like now.

The whole map can be rotated in 3D on his vertical axis.

That's all, i already know that Online Maps has many of these features but i would know if it completely fits my needs, especially about the 3D clustering.

Riccardo