Field Component: By
Gufm1 - Secular variation model for last 2ky (Jackson, Jonkers and Walter, 2000)

Contour of Component: By
image file of contour map using GMT

Image By (001)
Year 1590

Image By (003)
Year 1592

Image By (005)
Year 1594

Gauss coefficients
image file of graph using gnuplot

Gauss Coefficients n=1,2