Basic Topographic Map
In line with the needs of national economic construction, Ministry of the Interior adopted the orthographic projection methodology of analytical photogrammetry since 1976. Then the "1/5,000 basic maps" were produced which covered the area where the elevation is lower 1,000 meters above sea level and the "1/10,000 basic maps" were produced which covered the area where the elevation is higher 1,000 meters above sea level. After seven years, the overall national basic maps had been completed. In response to the trend of digital photogrammetry and mapping, it turned to utilize the digital method to surveying and production of basic maps since 1997. In 2004, the area where the elevation is higher 1,000 meters above sea level has changed to reproduced with scale 1/5,000. Then the basic maps covering the whole Taiwan area were completed using digital revision method in 2006.
Basic topographic map is the core and common data of NGIS. It is also the essential data of land-use planning, land conservation, disaster prevention and relief, economic development, etc. Since the huge changes raised in recent years, such as rapid economic growth, new town’s development, construction of industrial area, re-drawing of town and agriculture area, traffic and water conservancy construction, etc. In order to ensure the information consistent with the ground, the Ministry of the Interior continued to maintain the basic topographic maps of various scales, to meet the requirement of country's construction and the community needs to use map.