An authoring system and authoring method to assigning a real geo-spatial position to sensory-effect data representing virtual sensations, including a virtual sound sensation. The system includes an author interface for displaying a representation of a real geo-space, means for accepting the sensory-effect data, and means for an author to assign the virtual sensory effect data to a location within the displayed representation corresponding to a real location within the geo-space, such that a user has the sensation of the virtual sound coming from the location assigned for the sensory-effect data.