Chapter 1 Earth and Maps Section 1 Earth and Globe

Chapter 1 Earth and Maps Section 1 Earth and Globe

The shape and size of the Earth

The Earth is our home as human beings. What does this home look like?

The Earth is a sphere, which seems to be a simple question today, but in ancient times it was a difficult mystery to solve. The understanding of the Earth's spherical shape has gone through a long process.

The Earth's shape has now been confirmed by the use of artificial satellites, and the size of the Earth has been accurately measured.

Average radius: 6371 km; maximum circumference: about 40,000 km; surface area: about 510 million square kilometers.

Model of the Earth One-by-One Globe

The Earth is too big, so in order to see the whole picture of it, people made a model of the Earth, a globe, by reducing it to a certain proportion according to the shape of the Earth. On the globe, people use different colors, symbols and words to indicate the location, shape and names of land, ocean, mountains, rivers and lakes, countries and cities. The globe makes it easy to know what the earth looks like. Learn about the characteristics and distribution of various geographic objects on the Earth's surface.

When you turn the globe, you can see that it rotates around an axis. This axis represents the earth's axis. In fact, this axis does not exist on the Earth, it is an imaginary axis. The two points where the earth's axis intersects the earth's surface are called the poles. The point opposite the direction of the North Star is called the North Pole, which is the northernmost point on the Earth. The point corresponding to the North Pole is called the South Pole, which is the southernmost point on Earth.

Latitude and Latitude

On the globe, the large circle that is equidistant from the North and South Poles is called the equator. All circles parallel to the equator are called lines of latitude. The equator is the largest circle of latitude. The lines of latitude narrow to a point at the north and south poles. The lines of latitude indicate the east-west direction.

The equator has a latitude of 0° and is the starting line of latitude. From the equator to the north and south, each is divided by 90°, called the northern and southern latitudes, denoted by N and S, respectively. The North Pole and the South Pole are each 90°.

People stipulate that the global 0° to 30° is the low latitude region, 30° to 60° is the middle latitude region, and 60° to 90° is the high latitude region.

Longitude and longitude

On the globe, the line connecting the north and south poles and perpendicular to the line of latitude is called the meridian. The meridian indicates the north-south direction.

The longitude of the prime meridian is 0°, which is the starting line of longitude. This is divided into 180° to the east and 180° to the west, and is called the eastern and western longitudes, denoted by E and W, respectively. The 180° east and west longitudes coincide and are usually referred to as the 180° meridian.

Any two opposing meridians form a meridian circle; any one of them can divide the Earth into two hemispheres.

Positioning using the latitude and longitude grid

In our daily life, we often hear or see the following similar reports.

On a globe, the longitude and latitude lines intertwine to form a latitude and longitude network. The latitude and longitude position of any location on the earth's surface is the intersection of a certain line of longitude and a certain line of latitude.

A ship sailing on the vast ocean and an airplane soaring in the vast sky can use the latitude and longitude network to determine their positions and facilitate navigation. Therefore, the use of latitude and longitude networks to locate navigation, aviation, transportation, military, and meteorological observation, and many other aspects, have a wide range of uses.

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