Geography
Tools and themes
The five themes - location, place, human–environment interaction, movement, and region - organize almost every question. Know absolute location (latitude and longitude, address) versus relative location (described in relation to something else). Latitude lines run east–west but measure distance north or south of the equator; longitude lines run pole to pole and measure east or west of the prime meridian. Map projections always distort shape, area, distance, or direction; Mercator preserves direction and exaggerates high-latitude area, while equal-area projections preserve area.
Physical and human systems
Physical geography covers plate tectonics, weathering and erosion, climate controls (latitude, altitude, water bodies, wind patterns), and biomes. Human geography covers population distribution and density, push and pull migration factors, urbanization, cultural diffusion, language and religion regions, and economic activity from primary (extraction) to quaternary (information) sectors.
Reading maps and data
Scale, legend, and orientation come first. Choropleth maps shade whole regions by value; dot density shows clustering; isoline maps connect points of equal value. In population pyramids, a broad base indicates high birth rates and a young population.
Traps
Frequent errors: swapping latitude and longitude; confusing weather (short-term) with climate (long-term averages); assuming the equator is the hottest place everywhere or that deserts are always hot; and treating a projection's distortion as an error to be corrected rather than a tradeoff.
Rule of thumb
Before interpreting any map, state the theme it shows and what the scale and legend measure. Worked example: a shaded map of states by median income is choropleth; conclusions about cities within a state cannot be drawn because the unit of analysis is the state.