The hotspot technology is used for adding a large number of
interactive objects to the map.
Images of objects are added to the map
using the "image layer".
To create it, use the Layer class.
Information about objects (their boundaries and positions) is stored on the server
and added to the map through the hotspot layer.
To create this layer,
use the hotspot.Layer class.
Before creating the hotspot layer, we must create the data source —
the object that will be requesting the hotspot data from the server.
The data source is implemented by the hotspot.ObjectSource class.