The surveying method used by Ino is called as “Dosen-Ho”，a kind of open traverse method. “Dosen”，that is to say，surveyed polygonal lines along coasts and main roads compose a net. Nodes on the net are points of bifurcation and/or points of confluence because the lines are directed. Then errors of closure would be apparent at the confluence points of the surveying lines. This paper deals with the error handling by Ino to make maps. He distributed the revealed error at the confluence point among adjacent points on the newly surveyed line and did not modify existing lines already surveyed.
