Resolution No.20 (1963): Aeromagnetic surveys for the WMS project

The IUGG recommends that the possibility be investigated of securing observations from aeromagnetic surveys made for geophysical prospecting purposes, particularly in regions where a vector or absolute aeromagnetic survey is available as a reference, and considers that the detailed maps are not needed by only a sufficient number of observations useful to the WMS project, for example, observations spaced approximately 20km apart.