Residual is what remains after regional magnetic trends are removed from the total intensity Residual maps show local magnetic variations, which may have exploration significance. The regional trend of the total intensity can be calculated using a number of techniques, including running averages, polynomials, low-pass filters, or upward continuation techniques. [[:file:using-magnetics-in-petroleum-exploration_fig14-2.png|Figure 1]] shows magnetic profiles of total intensity, regional trend, and residual. | Residual is what remains after regional magnetic trends are removed from the total intensity Residual maps show local magnetic variations, which may have exploration significance. The regional trend of the total intensity can be calculated using a number of techniques, including running averages, polynomials, low-pass filters, or upward continuation techniques. [[:file:using-magnetics-in-petroleum-exploration_fig14-2.png|Figure 1]] shows magnetic profiles of total intensity, regional trend, and residual. |