That would be 8 concentric lines.
http://en.wikipedia.org/wiki/Concentric
http://www.google.com/imgres?imgurl=http://www.survivaliq.com/navigation/PIC/image108.gif&imgrefurl=http://www.survivaliq.com/navigation/elevation-and-relief_par3.htm&h=239&w=354&sz=8&tbnid=54upwF7XSiVbuM:&tbnh=82&tbnw=121&prev=/images%3Fq%3Dcontour%2Blines&zoom=1&q=contour+lines&hl=en&usg=__lLphVuI6wK3pGfpupxe9YsnN0PM=&sa=X&ei=1dVdTduPLMHFgAesqN3jDA&ved=0CC4Q9QEwBA
On a topographic map, how would you show a hill with an elevation of 80 feet if the contour interval is 10 feet?
1 answer