Amap blank, or key, explains the meaning of symbols that represents earth or a part of it

Cartographers use symbols torepresent geographic features. ... A map usually has a legend, or key, that gives the scale of the map andexplains what the various symbols represent. Some maps show relief, or changes in elevation. A common way to show relief is contour lines, also called topographic lines

answer; the edward snowden leaks of nsa classified material;