Geographers use the term "area" to refer to any particular portion of the Earths surface. It may be as small as a park or a neighborhood, or as large as a continent or an ocean. Metropolitan areas, for example, help define the borders of large population centers for a census and other official purposes. The metropolitan area of Tokyo, Japan, contains many cities and over 35 million people.

Area is also an exact measure of the size of a surface with specific boundaries. For example, the U.S. state of California has a land area of 403,932 square kilometers (155,959 square miles).

For maps, its important to represent area accurately so the sizes of different regions can be compared properly. The surface of a sphere such as the Earth can never be perfectly reproduced on a flat map. As a result, mapmakers, or cartographers, use different types of distortions, or projections, depending on which features they want to show most accurately. A Mercator projection distorts area but preserves accurate directions; the Mollweide projection shows area accurately but tends to distort directions and shapes.

area
Millions of people live and work in Tokyo.

Small and Tall
The smallest unit of area is Planck area, expressed as a decimal point followed by 70 zeroes, then 261. The largest unit of area is the yottameter, expressed as a 1 followed by 24 zeroes.

Noun

a geographic region.

atmosphere (atm)
Noun

(atm) unit of measurement equal to air pressure at sea level, about 14.7 pounds per square inch. Also called standard atmospheric pressure.

Noun

program of a nation, state, or other region that counts the population and usually gives its characteristics, such as age and gender.

Noun

one of the seven main land masses on Earth.

distortion
Noun

representation that is twisted, mistaken, or false.

Noun

our planet, the third from the Sun. The Earth is the only place in the known universe that supports life.

geographer
Noun

person who studies places and the relationships between people and their environments.

map projection
Noun

method by which shapes on a globe are transferred to a flat surface.

Mercator projection
Noun

representation of a sphere where lines of latitude and longitude are straight and at right angles to one another.

metropolitan area
Noun

region surrounding a central city and has at least 15 percent of its residents working in the central city.

Mollweide projection
Noun

representation of a sphere where area is shown accurately but directions and shapes are distorted.

Noun

an area within a larger city or town where people live and interact with one another.

Noun

large body of salt water that covers most of the Earth.

Sinusoidal Equal Area projection
Noun

representation of a sphere where area is shown accurately but directions and shapes are distorted.