United States and World Geography: Place, Space, and Systems
Coordinates and time
Latitude measures north-south (equator 0°); longitude measures east-west (prime meridian 0°, International Date Line near 180°). Earth rotates 360° in 24 hours, so each 15° of longitude equals one hour.
Physical systems
Climate is shaped by latitude, altitude, ocean currents, continentality, and rain shadows. Plate boundaries are divergent (spreading), convergent (collision, as with the Himalaya), and transform. The Ring of Fire traces Pacific subduction zones.
Maps and projections
Every flat map distorts area, shape, distance, or direction. Mercator preserves direction but exaggerates high-latitude area; Robinson and equal-area projections trade one distortion for another. Scale converts map distance to ground distance.
Regions and chokepoints
U.S. regions: Northeast, South, Midwest, West. Strategic straits include Hormuz, Malacca, Suez, Panama, the Bosphorus, and Gibraltar.
Population
Demographic transition moves from high birth and death rates to low ones, passing through rapid growth. Urbanization tracks economic development.
Traps
Confusing latitude with longitude; assuming latitude alone determines climate; mixing up country borders; forgetting that projection choice changes apparent size; treating a chokepoint's importance as purely military rather than economic.
Worked example
City A is at 90°W and City B at 75°E. Difference = 90 + 75 = 165°; 165 ÷ 15 = 11 hours. Because B is east, B's local time is 11 hours ahead.
Rule of thumb
For any geography question, ask three things: absolute location, physical setting, and human use. Most answers hinge on the interaction among them.