A method of integrating an external 3D visualization product into a 2D GIS system to provide an interactive 3D interface through which GIS functions can be performed, wherein • the 2D GIS system is adapted to process 2.5D GIS data for visualization, placement, editing, and analysis using 2D views that include representations of elevation, and comprises a 2D rendering engine and a mapview controller, and • the 3D visualization product comprises a 3D rendering engine, characterized in that the method comprises: • providing an interface between the 2D GIS system and the 3D visualization product, the interface comprising □ an engine interface that interfaces with the 3D rendering engine, and □ a mapview controller interface that is adapted to receive rendering data from the 2D rendering engine and from the engine interface and to pass the rendering data to the mapview controller; • providing, by the interface, GIS information received from the 2D GIS system to the 3D visualization product; • providing, by the interface, 3D rendering data from the 3D visualization product to the 2D GIS system, wherein 3D visualization components are mapped to 2D representations by the interface; • producing, by the 2D GIS system, a display in a 3D window on a display device including 3D graphic indicia from the 3D rendering data and GIS information from the 2D GIS system, the 3D graphic indicia being displayed in a geospatial manner as a function of the GIS information; • allowing a user to manipulate the 3D graphic indicia within the 3D window; and • mapping, by the mapview controller interface, user selections made in the 3D window to corresponding 2D geo-location coordinates for use by the 2D GIS system. • the 2D GIS system is adapted to process 2.5D GIS data for visualization, placement, editing, and analysis using 2D views that include representations of elevation, and comprises a 2D rendering engine and a mapview controller, and • the 3D visualization product comprises a 3D rendering engine, • providing an interface between the 2D GIS system and the 3D visualization product, the interface comprising □ an engine interface that interfaces with the 3D rendering engine, and □ a mapview controller interface that is adapted to receive rendering data from the 2D rendering engine and from the engine interface and to pass the rendering data to the mapview controller; □ an engine interface that interfaces with the 3D rendering engine, and □ a mapview controller interface that is adapted to receive rendering data from the 2D rendering engine and from the engine interface and to pass the rendering data to the mapview controller; • providing, by the interface, GIS information received from the 2D GIS system to the 3D visualization product; • providing, by the interface, 3D rendering data from the 3D visualization product to the 2D GIS system, wherein 3D visualization components are mapped to 2D representations by the interface; • producing, by the 2D GIS system, a display in a 3D window on a display device including 3D graphic indicia from the 3D rendering data and GIS information from the 2D GIS system, the 3D graphic indicia being displayed in a geospatial manner as a function of the GIS information; • allowing a user to manipulate the 3D graphic indicia within the 3D window; and • mapping, by the mapview controller interface, user selections made in the 3D window to corresponding 2D geo-location coordinates for use by the 2D GIS system.