Meridian, also known as meridian, is an arc on the earth's surface connecting the north and south poles and perpendicular to the equator. All the great circles on the earth that pass through the earth's axis plane are called "warp circles". A semicircle separated by two poles by a coil is called a meridian. The length of meridian is about 20037km, and any two meridians are equal in length and intersect at the north and south poles.
major feature
Meridian refers to all the great circles on the earth that pass through the earth's axis plane, which are called "warp coils". The semicircle in which the meridian circle is divided by two poles is called "meridian", that is, "meridian". Meridian represents the local north-south direction. The longitude of each point on the same meridian is the same. That is, the great circle formed by the intersection of the plane passing through the earth axis and the ground is called the warp circle.
All the warp circles intersect at the north and south poles and are divided into two semicircles by the poles, which are called "warp" or "warp". Longitude indicates the north-south direction; Orthogonal to all parallel lines. Every meridian on the earth is roughly equal in length.
Named source
The origin of meridian naming: in the apparent trajectory of a celestial body, all points on the same meridian appear at the same time as the upper meridian (noon) and the lower meridian (child). When different meridians have different places. The east is early and the west is late.
There is international controversy about the demarcation of the boundary between the eastern and western hemispheres. It was not until 1953 that Greenwich chose 20 W and160 e as the dividing line between the eastern and western hemispheres.
The zero-degree meridian on the earth is called the prime meridian or Greenwich line. The zero meridian goes straight to the former site of Greenwich Observatory in London. The warp length is about 20037km, and each warp length is the same.
The longitude and latitude lines are drawn on globes and maps to determine the position and direction on the earth, but they are not drawn on the ground.
However, you can easily see the longitude of your place: stand a bamboo pole on the ground. When the sun rises at the highest point at noon, the shadow of the bamboo pole is the longitude of your place. Because the meridian represents the north-south direction, it is also called the meridian.