National Geographic : 1976 Jul
as flatlands. The height of the surface at any point is propor tional to the density of the popu lation at that place. The three part graphic view dramatizes the vast population shifts of a continent in transformation. MINNEAPOLIS-ST. PAULA ST. LOUIS _ I-- ; CHICAGO PHILADELPHIA CLEVELAND DETROIT PITTSBURGH BALTIMORE WASHINGTON AIA AI ' -CHARLESTON SAVANNAH NEW ORLEANS TAMPA ST. PETERSBURG CHICAGO / NEW YORK BOSTON 1976 Now 215 million strong, Americans have settled the length and breadth of the land. Although cities loom large, they occupy less than 2 percent of the landscape-yet within that 2 percent live two out of three Americans. SNEW YORK PHIA BOSTON Settlers, sodbusters, cityfolk BOSTON THESECOMPUTERMAPSBY THELABORATORYFOR COMPUTERGRAPHICSANDSPATIALANALYSIS, HARVARDUNIVERSITY,ARE BASEDON CENSUSES CLOSELYRELATEDTOTHE NATION'SANNIVERSARIES: 1790 (THE FIRSTTO BETAKEN), 1870, AND 1970. THUSTHE BOTTOMMAPSHOWSA SLIGHTLYGREATER DENSITYOF POPULATIONTHAN ACTUALLYEXISTED IN 1776, ANDTHEOTHERTWO A FRACTIONLESS.