Isohyets

http://www.greenstone.org/greenstone3/nzdl%3Bjsessionid=D67665AFD956C505391B5CEE8BAD4E22?a=d&c=envl&d=HASH51b2a65afcdd1420ccb2bd.2.np&sib=1&p.s=ClassifierBrowse&p.sa=&p.a=b

Isohyets are lines on a map connecting areas of equal amounts of rainfall over a given period of time. This is a map of Africa with isohyet lines marking similar areas of rainfall across the area.