Dictionary:Logarithmic contour interval

(lo, g∂ rith’ mik) Plotting of data on a logarithmic scale is sometimes used where properties of materials vary by many orders of magnitude. Resistivity and IP data often are contoured in intervals that are approximately logarithmic (or geometric), such as 1, 2, 5, 10, 20, 50, 100; or 1, 3, 10, 30, 100, 300.