Isopach Map

http://www.maf.govt.nz/mafnet/rural-nz/emergency-management/volcanoes/volcano-eruption-impact/volimpact-05.htm

This is an Isopach map. Isopach maps show the thickness of a certain stratum. They are usually used for geological reasons. This map shows the deposits of a volcano. Taupo is an 1800 old volcano that erupted devistating much of the surrounding area. By this map they you can tell where the deposits went and how thick/heavy they where. You can tell the further from the volcano you get the less dense the deposits get.