Abstract
Mobile recording magnetometers were developed during and after World War II. These new instruments have permitted the recording of long magnetic profile lines. These long magnetic profiles have clearly shown that two distinctly different types of anomalies occur. Many local anomalies are found with amplitudes up to a few thousand gammas and widths up to a few hundred kms. Very large regional anomalies are found with amplitudes of tens of thousands of gammas and widths of several thousands of kms. There are no noticeable anomalies between there two types.
It is suggested that world magnetic charts made to a scale of less than 1/30, 000, 000 should be smoothed so as to eliminate the effect of all local anomalies on the isoline shapes. The characteristics of local anomalies could be indicated on the chart by a color coded scheme which in effect would indicate a chart error which might be expected because of local anomalies in the area.
