Introduction
GSI, being the competent authority of the Survey Act, conducts national surveying and mapping activities, which provide a basis for the land management. Historically it dates back to 1869 when cadastral Registration Map Section was established in the office of Geography Department, Ministry of Civil Service. Later in 1888 it was reorganized as Japanese Imperial Land Survey, and finally in 1945 it became the Geographical Survey Institute. In April 2010, the official English appellation is changed to "Geospatial Information Authority of Japan." The surveys GSI performs provide positional data (longitudes and latitudes) of the land and elevations from the mean sea level. A triangulation point and a benchmark give the exact position and elevation of that particular point on the earth, respectively. Today in addition to them GPS-based control stations are established for precise positional measurements where signals from the GPS satellites are continuously observed. These control points are widely used for such purpose as public surveys executed by the national government and other public organs, for observations of crustal movements through continuous and repeated surveys, and for researches for disaster prevention including studies on earthquakes. Preparation of various base maps, notably the topographical map series of 1/25,000 that cover the whole country, is another important task of GSI. Those maps are used as a basis for maps diverse public and private sectors prepare, such as administration area maps, road maps, GSI compiles several thematic maps (Land Use Map, Land Condition Map, Volcanic Land Condition Map, Map of Active Faults in Urban Area, etc.), which are an effective tool for disaster prevention efforts and national development. These maps are available in paper and in digital form (CD-ROM). Aerial photographs are also published. Addressing the needs of the times we have introduced a new infrastructure concept, which we have been promoting as "Digital Japan" a virtual and real-time representation of the land realized by integrating various geospatial information and made accessible to anyone on the internet. As a sole responsible organ for national survey and mapping, we have been actively engaged in international cooperation in the field of survey and mapping and geosciences as well.
