<P> Various geological data are rendered as contour maps in structural geology , sedimentology , stratigraphy and economic geology . Contour maps are used to show the below ground surface of geologic strata , fault surfaces ( especially low angle thrust faults ) and unconformities . Isopach maps use isopachs ( lines of equal thickness ) to illustrate variations in thickness of geologic units . </P>
<P> Various geological data are rendered as contour maps in structural geology , sedimentology , stratigraphy and economic geology . Contour maps are used to show the below ground surface of geologic strata , fault surfaces ( especially low angle thrust faults ) and unconformities . Isopach maps use isopachs ( lines of equal thickness ) to illustrate variations in thickness of geologic units . </P>
contour line on map connecting points of equal stratigraphic thickness
contour line on map connecting points of equal stratigraphic thickness
isopachs
isopachs