Investigation of Height of Local Magnetic Anomaly at Port Snettisham, Southeastern Alaska

Abstract

Introduction—During the past few years the demands upon the United States Coast and Geodetic Survey .for reliable aeronautical charts has greatly increased owing to the number of. small privately owned aircraft that have come into use. The owners of these planes demand more information regarding the local magnetic anomalies over the main traveled routes. The present charts show the isogonic lines for conditions encountered on the ground or the magnetic courses to important air‐ports. As the majority of these small planes are equipped only with a magnetic compass for cross‐country navigation, a knowledge of the effect of local and regional magnetic anomalies on these compasses has been desired. This investigation has been confined to a local anomaly existing in southeastern Alaska.