Geodetic Aspects of Delimitation and Demarcation of Land Boundary between Indonesia and Malaysia in Sebatik Island

摘要

Indonesia and Malaysia has a land boundary in Borneo (Kalimantan) island, with boundary line of about 2004 km long. The boundary line has been defined by the boundary conventions between the Netherlands and United Kingdom (Britain) in 1891,1915 and 1928, respectively. In these conventions the boundary line is defined by combination of watershed, latitude, river, and straight line. Demarcation survey of land boundary between Indonesia and Malaysia has been started by the Netherlands and Britain, although only related to small boundary portion. Indonesia and Malaysia continue the survey since early 1970s. Up to know there are still several disputable boundary problems along the border, which are usually termed OBP (Outstanding Boundary Problems); which one of them is in Sebatik Island, along the border between East Kalimantan (Indonesia) and Sabah (Malaysia). In Article IV of 1891 London Convention the boundary line in Sebatik island is defined as parallel (latitude) line of 4~0 10' N. Delimitation and demarcation of this astronomical parallel line in the field is still disputable, although several boundary monuments have been established and coordinated during the 1912 Joint Survey between Great Britain and Netherland and the 1982-1983 Joint Survey between Indonesia and Malaysia 1982-1983. The coordinate differences obtained from those surveys, the geodetic datum that should be used for the coordinates of boundary points, and the deflection of vertical estimation, are the issues that still have to be settled down by the two countries. Those two sets of coordinates will also be compared with the coordinates obtained from the 2012 GPS survey conducted by the Indonesian side. This paper presents and discusses geodetic interpretation and analysis of this boundary problem in Sebatik Island, and sum up with some conclusions and recommendation.