A Map Room in Asterfield
Asterfield is a small farm town surrounded by fields and low hills. The town hall was preparing a traveling exhibit about how maps help people understand places. The map team wanted visitors to compare a globe with several flat maps. A globe shows Earth on a round surface. A flat map is made by using a map projection, or a method for showing the curved Earth on a flat surface.
The team taught visitors to read coordinates. Latitude lines run east to west, but they tell how far north or south a place is from the equator. The equator is 0° latitude. Longitude lines run from the North Pole to the South Pole, but they tell how far east or west a place is from the Prime Meridian. The Prime Meridian is 0° longitude. A coordinate pair lists latitude first and longitude second. The letters N and S show north or south, while E and W show east or west.
The exhibit included five location cards. The card for Asterfield read 39.1° N, 98.2° W. Anchorage, Alaska, was listed as 61.2° N, 149.9° W. Quito, Ecuador, was listed as 0.2° S, 78.5° W. Nairobi, Kenya, was listed as 1.3° S, 36.8° E. Tokyo, Japan, was listed as 35.7° N, 139.7° E. A place's coordinate pair works like an address: it narrows a location to the crossing of one latitude and one longitude.
The team also compared projections. A Mercator projection can make directions and local shapes easier to read, but places near the poles appear much larger than they are compared with places near the equator. A Robinson projection balances several kinds of distortion, so it is often used for a broad view of the world. A conic projection can be useful for a large east-west region in the middle latitudes, such as the continental United States.
The map team reminded visitors that no flat projection shows every distance, shape, direction and area perfectly at the same time. A globe avoids flattening Earth, although small details can be harder to see. A mapmaker chooses a representation according to the question being asked. The town's display used the globe for checking the general arrangement of continents and the flat maps for comparing different ways to show locations.