The Office of Information Management and Technology in Hawaii (the U.S.) offers a 3D geographic information system (GIS) map, which covers 19,500 measured buildings of Honolulu, as a part of its open data program. Likewise, other countries, such as China and India with new and proposed smart cities, are predicted to adopt 3D-based virtual reality geographic information systems (VRGIS). Since 3D GIS is an extension of GIS, it becomes important to get acquainted with the basic term.