Abstract：Shift sampling theory is a theory about algorithm and calculation errors of Fourier transform. Its developments to the original theory are a more generalized novel algorithm,the corresponding error expression,and a further vvay to reduce error and raise accuracy. The error equation of a real reduction-to-the-pole algorithm under this theory shows that oscillation and distortion which get more severe toward lower latitude in reduction-to-the-pole in lozv latitude area result from the limitation of existing algorithm in Fourier transform,instead of potential function or Fourier transform itself. After knowing the origins of these phenomena,vve used shift sampling theory to solve the problem quite desirably,thus making reduction-to-the-pole in lovv latitude area(even on equator)become possible and rather accurate. The technique avoids the restriction which latitude causes on magnetic anomaly reduction-to-the-pole in zvavenumber domain. The technique will play an important role in magnetic data interpretation,particularly in magnetic data interpretatlon near or on equator.
