Study Of 1∶250,000 Database Update

1:250,000 national geo-information Database is our country's foundational Database. This Database mainly uses 1:250,000 terrain map that was completed in the beginning of eighties by digitization as base map. The contents in the map happened more than twenty years ago. But those years is a period of quickly development of our economy because of its reformation and opening. This makes the present situation of current map lag behind the development request, so it's present situation and veracity can't be show and it directly affects the usage of survey production and survey guarantee. Therefore, the update of 1:250,000 geo-information Database become a most urgent problem.This paper discusses the organization of 1:250,000 national geo-information Database update project and analyzes the data source of its. Based on it, this paper proposes some update methods for 1:250,000 national geo-information Database. In the course of 1:250,000 geo-information Database update implement by RS images, this paper discusses the drawing of pretreatment map and the pretreatment of map. To RS image, this paper uses many methods to handle it, such as rectification, overlay, fusion, mosaic, and cut by map sheet etc. Many methods for information detection and bound abstraction in RS images are discussed too.Finally, the technic flow of national traffic network update with GPS is provided to reader too. Quality control and management go through the processing of Database update.