The Pinebarrow Coordinate Atlas

A River Port Looks Around the World

Pinebarrow is a river port in the middle of the United States. Barges there load corn, beans, and sunflower seeds from nearby farms. At the town library, a group called the Harvest Atlas Team is making a display about places where farm products are grown and traded. The team wants visitors to understand locations, not just memorize place names.

The team uses latitude and longitude. Latitude measures how far north or south a place is from the equator. Lines of latitude are called parallels because they circle Earth without meeting. Longitude measures how far east or west a place is from the prime meridian, the line marked 0° longitude. Lines of longitude are called meridians, and they meet at the poles. A coordinate is written with latitude first and longitude second.

The team records these approximate coordinates: Pinebarrow, 40° N, 90° W; New Orleans, 30° N, 90° W; Anchorage, 61° N, 150° W; Quito, 0°, 78° W; Tokyo, 36° N, 140° E; and Cape Town, 34° S, 18° E. The letters N and S show north or south of the equator. E and W show east or west of the prime meridian. The equator itself is 0° latitude.

A globe shows Earth as a round object, so it avoids the stretching that happens when a round surface is put on a flat page. Flat maps use projections. A Mercator projection keeps many local angles and directions useful for navigation, but places near the poles can look much larger than they really are. An equal-area projection keeps area comparisons more accurate, although shapes may look different. A Robinson projection balances several kinds of distortion for a broad view of the whole world; it does not keep every distance, shape, or area exact.

The team chooses a display for each question. A globe helps visitors see the general relationship of continents. An equal-area map helps compare the sizes of farming regions. A Mercator map can help trace a route by direction. A Robinson map gives a readable world view for the library wall. The team writes the projection name beside each map so visitors know that every flat map makes some trade-offs.