Latitude and longitude is a coordinate system composed of longitude and latitude. It is a spherical coordinate system that uses the spherical surface of three-dimensional space to define the space on the earth, and can mark any position on the earth.

Latitude, like longitude, is an auxiliary line assumed by human beings for the convenience of measurement, which is defined as the trajectory formed by a point on the earth's surface with the rotation of the earth. Any latitude is round and parallel to each other, and the length of latitude is the circumference of equator multiplied by the cosine of latitude, so the longest latitude of equator, the farther away from equator, the shorter the circumference, and it will shrink to zero at both poles.

Development history

In 120, a young man studied astronomy and geography in this ancient library. This is Claudius Ptolemy. Ptolemy integrated the previous research results, thought that maps should be drawn according to fixed points with known latitude and longitude, and put forward the concept of drawing latitude and longitude network on maps. To this end, Ptolemy measured the latitude and longitude of important cities and strongholds in the Mediterranean region and compiled eight volumes of geographical works, including the latitude and longitude of 8000 places.

In order to draw the longitude and latitude lines on the earth on a plane, he tried to draw them into simple sectors, thus drawing the famous Ptolemy map.

The key to measuring latitude and longitude correctly is to have a "standard clock". It is obviously more convenient and practical to make accurate clocks at sea than to rely on celestial bodies. /kloc-the progress of mechanical technology in the 0/8th century has finally created conditions for solving this long-standing problem. Harrison, a watchmaker in Yorkshire, England, spent 42 years making five timepieces in succession, each of which is more accurate and perfect, and the accuracy is getting higher and higher.