Szemle: USA national atlas, ground water & population

Summary

This paper reviews two thematic maps from the National Atlas of the United States. The first, a groundwater map (1967, scale 1:7,500,000), uses distinct colors to differentiate unconsolidated and consolidated aquifer rocks, marking sources yielding at least 3.5 l/sec of fresh water and major springs producing over 100 million m³ annually, thereby presenting the nation's hydrogeological conditions and water-supply potential. The second, a population map (1968), employs county-level (1:17M) and state-level (1:34M) scales with multi-color choropleth and diagrammatic methods to depict urban-rural population changes from 1950 to 1960, population change patterns between 1940-1950 and 1950-1960, and selected socio-economic indicators from the 1960 census. Both maps combine substantive content with high-quality cartographic execution.