PURPOSE : A method for offering real estate information using an Internet digital topographical map based on a GIS(Geographical Information System) is provided to develop a topography database including a topographical contents certificate to all geographic position information and facility information by applying a topographical contents certificate database to a current GIS, and enable all clients to freely inquire the Internet digital topographical map in the web.CONSTITUTION : The topography database is constructed by databasing the GIS based on the topography. An Internet homepage for offering an Internet topographical map service based on the topography database is constructed. If the client of users connected to the homepage requests the Internet digital topographical map, a web server transfers Internet digital topographical map information stored in the topography database, and detail real estate information such as a current price/real estate for sale, building information, and shop information to the client. Limited to a client request of the user, the web server connects the client to a website or an Internet call center of a real estate agent linked to the real estate information.? KIPO 2006