Isopachs

An isopach is a line on a map drawn through points of equal thickness of a designated unit (google definitions). The map above is a excellent example of an Isopach map, showing a debris-flow deposit in terms of centimeter thickness.

http://vulcan.wr.usgs.gov/Imgs/Gif/Projects/MassMovement/Flume_Sept01/flume_deposit_isopach_map.gif