Why is the application of GPS positioning technology a revolution in the history of surveying and mapping development?

Surveying and mapping is an ancient discipline, which is produced with human activities and is constantly enriched.

As far back as 4000 BC in ancient Egypt, after the Nile flooded, in the process of sorting out farmland boundaries, earlier measurement techniques were produced. Through astronomical observation, the ancient Egyptians determined that a year was 365 days, which was the general calendar of ancient Egypt during the ancient kingdom period (3000 BC). They determine their direction by observing the North Star. Every ancient Egyptian pyramid has a standard geometric size, which shows that people had a more accurate measurement method of length and angle at that time. In the 3rd century BC, Greek scientists used astronomical methods to measure the shape and size of the earth. In 340 BC, Aristotle, a Greek scientist, clearly pointed out in his book On Heaven that the shape of the earth is round. By observing Polaris at different latitudes, he calculated that the circumference of the great circle of the earth is 4× Stedia. Stedia is a unit of length commonly used in ancient Egypt and ancient Greece. It is not clear how long Stedia is.

China is an ancient civilization, and its surveying and mapping technology developed quite early. According to legend, Jiuding in the Xia Dynasty, which was more than two thousand years BC, is the original picture. The "left ruler" and "right ruler" that describe Dayu's flood control survey scene in Historical Records Xia Benji carry four hours to open Kyushu and connect nine roads to measure the height. "Rope" is the distance, "Gauge" draws a circle, and "Moment" draws a square and a triangle. At that time, there was another unit of measurement, namely "step", which converted 300 steps into one mile. Zhuan Xu Levin (25 13 ~ 2434 BC) began to observe the five stars of the sun and the moon, and set the length of one year. In the Qin Dynasty (246-207 BC), the length of a year was 365 and 25 days according to the Zhuan Xu calendar. Around the seventh century BC, that is, in the Spring and Autumn Period, Guan Zhong had collected early maps in his book Guan Zi. 1973 Silk maps of the early Western Han Dynasty, such as topographic maps, Zhu Bitu maps and urban maps, unearthed from the No.3 Han Tomb in Mawangdui, Changsha, are the earliest maps found in China at present. The Regional Map of Gong Yu compiled by Pei Xiu in the early Jin Dynasty is the earliest historical atlas in the world, and the Topographic Abbot Map compiled by Pei Xiu is the national map of China, which puts forward the earliest cartographic theory in the world. Fractional proportion, quasi-sight distance measurement method, tunnel measurement distance, height measurement height, right-angle inclination measurement angle and straightening measurement curves and straight lines. According to the theory of "painting six bodies", Jia Dan compiled a map of China people and foreigners at sea in the Tang Dynasty, which lasted for 17 years and the drawing format was 10 abbot.

From the 5th century BC to the 3rd century BC, China made the earliest guide tool "SiNa" with magnets, and published the earliest astronomical algorithm book "Zhou Bi suan Jing" in China in 1 century BC, in which the method of measuring height and distance by using the properties of right triangle was expounded. Around 400 AD, China invented the rice drum car, which is a tool to measure and determine the orientation by using mechanical principles such as gears. When you walk ten miles to make a bracelet, the compass on the car records the direction of the car. Around 720 BC, a group of monks in the Tang Dynasty (Zhang Sui) and others revised the old calendar as needed. Organized and led the first astronomical geodesy in ancient China, reaching Ulaanbaatar in the north and Changde in the south. In these places, they measured the length of winter solstice, summer solstice, the shadow of the sun and the height of the North Pole, and plotted the measurement results. The meridian length measured by them is the first time in the world. This measurement not only provides reliable data for revising the calendar, but more importantly, it also finds the difference of sun shadow. In Song Dynasty, Shen Kuo recorded the phenomenon of magnetic declination in his Meng Qian Bi Tan, which was the earliest discovery in the world. Shen Kuo has made great contributions to topographic survey engineering. He presided over the drawing of maps of all countries in the world, carried out topographic survey with a level and compass, and made a three-dimensional topographic model. "Wooden map" was earlier than the earliest terrain model in Europe, and Guo Shoujing, a great scientist in Yuan Dynasty, used self-made instruments to observe astronomy. It is found that the intersection angle between the ecliptic plane and the equatorial plane is 23 33' 05 ",which changes every year. According to the current theoretical calculation, the angle is 23 31'58 ",which shows that the observation accuracy in Guo Shoujing was quite high at that time. Guo Shoujing also invented some accurate formulas for checking internal angles and calculating spherical triangles, which provided a reliable mathematical basis for geodesy. At that time, it was to build water conservancy projects. Zheng He's nautical chart in Ming Dynasty is another masterpiece of surveying and mapping technology in ancient China.

Two. Modern measurement

/kloc-at the beginning of the 0/7th century, with the rise of the revolution in the asset stage, surveying and mapping science, like other sciences, has made great progress in adapting to the development of productive forces. /kloc-At the beginning of the 7th century, Hans, a Dutchman, invented the telescope, Sjol invented the triangulation method, and 1683 made an arc survey in France, which proved that the earth is an elliptical sphere with slightly flat poles. As the French all know, Trier proposed using contour lines to represent landforms, and German scientist Gauss proposed the least square theory. Then he put forward the theory of transverse cylindrical projection, which made the map measurement more accurate. /kloc-leveling method appeared in the 0/8th century, which improved the accuracy of topographic mapping. 1875 The establishment of the international metric convention made the international uniform unit of length, 1m defined as one fortieth of the meridian length passing through Paris. Photogrammetry theory developed in 1899. 1903 After the invention of the airplane, topographic maps were surveyed by aerial photography.

Around 1950s, the rapid development of electronics, computers, modern optics and space technology opened up a new road for the development of surveying and mapping science. The appearance of light waves from 65438 to 0947 has greatly changed the measurement of distance. In the 1940s, Baianping level came out, which made leveling more convenient and quick, and electronic theodolite came out. The reading mode has been greatly reformed, and the observation data can be automatically recorded and processed, which greatly improves the labor efficiency. Man is the sky of the earth's satellite, and satellite geodesy, a surveying and mapping discipline, has emerged. Satellite positioning is frequent, satellites take photos of the earth, monitor the changes of natural phenomena, and effectively survey deep mountains, deserts and oceans. The appearance of gyro theodolite improves the accuracy of mine orientation, probability statistics and linear algebra. , and the theory and method of engineering mathematics.

Since the beginning of17th century, surveying and mapping in China has developed. Emperor Kangxi of the Qing Dynasty led the national geodetic survey and map mapping. He first unified the length unit in the national survey, and according to the measurement results of meridian arc length, he personally decided to merge the earth meridian into 200 miles, each mile long 1800 feet, and each foot is one hundredth of the meridian length. He did not use missionaries to train talents and buy instruments, but successively surveyed and mapped North China. The maps of Northeast China, Inner Mongolia, Southeast China, Southwest China, Tibet and other places, and then the "Full Map of Asia" were all extremely important surveying and mapping achievements in the world at that time. From the late Qing Dynasty to the founding of New China, China's surveying and mapping industry developed slowly.

After the founding of New China, China's surveying and mapping industry has developed rapidly, and the surveying and mapping instrument manufacturing industry has grown from scratch. All kinds of precision instruments have been able to manufacture and construct the national astronomical geodetic network, precision leveling network and high-precision heavy knife network, and have completed the compilation of basic topographic maps with the scale of 50,000,1100,000 and small and medium-sized sample maps. Surveying and mapping industry is developing very rapidly.

Three. Contemporary surveying and mapping

The main symbol of contemporary surveying and mapping is GPS system. GPS global satellite positioning and navigation system is a new generation of satellite navigation and positioning system, which was developed by the United States in the 1970s. It took 20 years and cost 20 billion dollars, and was fully built in 1994. Have all-round real-time three-dimensional navigation and positioning capabilities by sea, land and air. The characteristics of GPS are all-weather, high precision, automation and high efficiency. It has won the trust of surveying and mapping workers, and has been successfully applied to geodesy, engineering survey, aerial photogrammetry, vehicle navigation and management system, crustal movement monitoring, engineering deformation monitoring, resource exploration, geodynamics and other disciplines, bringing a profound technological revolution to the field of surveying and mapping. With the continuous improvement of global positioning system (GPS) and software and hardware, the application field has been continuously explored, and now it has spread to all industries of national economy and gradually penetrated into people's daily life.