On this study, realtime GPS technique and combination of GPS/GLONASS technique are used to extracting coastline. Th￡ object of coastline is Gwanganri beach located in Busan. The coastline is observed along the traces of coastline when high wave of scar by using digital map of 1:1,000 and at random time zone, coastline is surveyed along the boundary line that is contacting with sea water level. When the coastline of random time zone is converted by height of tide table, the coastline when high wave of scar and converted coastline are shown as coincident approximately.