Isoline Map

http://www.oas.org/cdmp/document/apua/apu.htm

Isoline maps, also called contour line or isopleth maps, are a type of map with continuous lines joining points of the same value and for contour lines, those lines distinguishes points of equal altitude. These continuous lines, or isolines, are typically used in topographic maps to represent a 3-D surface of the world on a flat map, like hills or mountains. Isolines are then defined by a contour interval, which tells you the amout of elevational change between isolines, or contour lines. The above map is an isoline map of the different elevations of features around South America and the countries of Barbados, Trinidad, etc. Isolines or contour lines are visible throughout the map and consist of continuous lines joining points of equal elevation of certain features on the map. The elevation of said features are shown through the number given to the specific contour line. For example, the 100 ft contour line marks all areas on the map that are 100 ft in elevation.