Gravity and magnetic surveys on sea, land, or air invariably exhibit discrepancies at intersections of survey lines. These "misties" have to be removed before any meaningful contour map can be prepared. The misties are caused by many errors. Errors in location fixing, instrumental drift, diurnal magnetic variations, inaccuracies in Eoetvoes corrections because of errors in heading, and speed of ship or aircraft play a major role. Foster (1970) proposed a method for statistical estimation of the misties at line intersections with special reference to aeromagnetic data. The method can be extended to all gravity and magnetic surveys on land, sea, or air. However, it requires an approximately rectangular grid of survey lines. In case the network is irregular and there are lines in various directions crossing each other, Foster's method would not be applicable.