There is a concept of a navigable "Scene". The expance of a Scene is dependent on the source of the imagery and the imagery's projection system. For data in the Geographic projection system, the expanse is the entire globe. Effectively there is one Scene. For UTM data, there are sixty Scenes, each covering approximately six longitude degrees. Projection Methods You are dealing with "Projection Systems" anytime you are dealing with a map or a globe. For our purposes within the TerraService, the earth is a sphere. Points on it are referenced by Longitude and Latitude "lines". They are not lines really, but complex curves. Maps are flat drawing of earth. Satellite or aerial imagery, in its raw state, is more-flat-than-its round. It is mathematically impossible to present a sphere on a flat surface without distorting something. Cartographers have dealt with this issue for centuries by developing different methods, known as map projections, for representing...