What is a 3S system and what is its function?

1. What is "3S" technology? "3S" technology is a general term for the last prefix in English remote sensing technology, geographic information system GIS and global positioning system GPS. Second, why do "3S" technologies "come together"? ... human beings have a dream that they want to manage everything in the world in a way. Remote sensing technology (RS), geographic information system (GIS) and global positioning system (GPS) have natural complementary advantages, so they naturally "come together". They play different roles in 3S system, and remote sensing technology is the main force of information collection (extraction). Global Positioning System (GPS) locates remote sensing images (photos) and information extracted from them, endows them with coordinates, and enables them to be nested with "electronic maps"; Geographic information system is the "big housekeeper" of information. ..... organically combine the three, and the human dream will come true. "3S" is a dynamic, visible, constantly updated and three-dimensional system, which can be transmitted through the computer network and can be used in different regions and levels. 3. What is remote sensing technology? ..... "Remote sensing", as the name implies, is remote sensing. Every object on the earth is constantly absorbing, emitting and reflecting information and energy. One of them, electromagnetic wave, has long been recognized and used by people. It is found that electromagnetic wave characteristics of different objects are different. Remote sensing is based on this principle to detect the reflection of electromagnetic waves and the electromagnetic waves emitted by surface objects, so as to extract the information of these objects and complete the long-distance identification of objects. .. although the actual operation of remote sensing technology is very complicated, its achievements can be used every day in our lives! You can watch the "weather forecast" on TV every day. The "satellite meteorological cloud picture" played in the "weather forecast" is the image of "cloud" shot by "meteorological satellite". Meteorological observation is just one of many applications of remote sensing technology. .. all kinds of satellites achieve different purposes through different remote sensing technologies, such as meteorological satellites used for meteorological observation and forecasting; Ocean color satellite for ocean observation; Land resources satellites are used to investigate all land, forests, rivers, minerals and environmental resources on land; Radar satellites are all-weather (whether cloudy or foggy) and all-day (whether night or day), and can penetrate some ground objects (such as water, vegetation and land). The load tools used in remote sensing technology are not only satellites, but also tripods, airplanes, balloons, model airplanes, cars and cameras of the space shuttle, thus realizing the application of remote sensing technology at different heights and serving our different work purposes. At present, the most commonly used technologies are satellite remote sensing and aerial remote sensing. 4. How about remote sensing imaging? Generally speaking, there are two imaging methods of remote sensing technology: the first is the film shot by the camera, which is basically the same as that used in our daily life, but the difference is that the professional camera for remote sensing is bigger, and of course the film is correspondingly bigger. Some films are special films, such as "color infrared" special films. Develop, print and enlarge the film to become a remote sensing photo; The second is "digital imaging", and the imaging principle is similar to the TV we watch. Television programs are digital telecommunication signals transmitted by TV stations, which spread in the air, and then the signals are received and played by users' TV sets. After the signal transmission of the image is completed, "visualization" is realized. Remote sensing technology can also be understood as the above-mentioned information transmission process, that is, the ground information is "photographed" by the equipment on the satellite, and then the photographed signal is transmitted to the computer for playback, so that we can see the remote sensing image! 5. What is the resolution of remote sensing image? > Resolution is the smallest unit of measurement for recording data, which is usually used to describe the number of points (rows and columns) that can be displayed on a display device or the area represented by pixels in an image. ... because the "photos" taken by remote sensing are remote sensing "photos" (images, data, images, etc. ) These remote sensing images are obtained by "photographing" equipment with different resolutions on different carriers (such as airplanes and satellites) at different heights and in different "photographing" (acquisition) ways. The definition of these remote sensing images is different. Similarly, in our daily life, we take a picture of a tree with a "135" camera, a picture from a car and another picture from an airplane. When two "135" negatives magnify the same tree, the magnifying effect is different. It must be that the low-altitude "135" photo has the clearest effect after enlargement, which means the highest resolution. The flying height of remote sensing satellites is generally between 4000km (km) and ~600 km (km), and the image resolution is generally between 1 km (km) and 1 m (m). What does image resolution mean? It can be understood that one pixel represents the area of the ground. What does pixel mean? A pixel is equivalent to a point on the TV screen (TV is an image picture composed of several points), a pixel on the computer screen, and a group of people holding different color swatches form one picture. When the resolution is 1km, one pixel represents the area of the ground 1kmX 1km, that is, 1km2 (square kilometers); When the resolution is 30m, one pixel represents an area of 30mX30m on the ground; When the resolution is 1m, that is to say, one pixel on the image is equivalent to the ground area of 1m x 1m, that is, 1m2 (square meter). When you use remote sensing image data, please note that for the work problem you want to solve, you should choose remote sensing data with corresponding resolution. For remote sensing data templates, please check the "Satellite Remote Sensing Images" section of this website. 6. What are the uses of remote sensing images? Just like photos taken in our life, remote sensing photos can also "extract" a lot of useful information. From a person's photo, we can distinguish the information of his head, body, eyes, nose, mouth, eyebrows, hair and so on. Remote sensing photos (images) can distinguish a lot of information, such as water (rivers, lakes, reservoirs, salt ponds, fish ponds and so on. ), vegetation (forests, orchards, grasslands, crops, swamps, aquatic plants, etc. ), land (farmland, woodland, residential areas, factories and mines, enterprises and institutions, deserts, coasts, wasteland, roads, etc. ) and mountains. Small objects such as trees, people, traffic signs and football field signs can be identified from remote sensing images. The extraction of a large amount of information undoubtedly determines the wide application of remote sensing technology. According to statistics, remote sensing technology can be applied to nearly 30 fields and industries. Because remote sensing technology "takes pictures" from a height where people can't stand generally, it also has advantages that human beings can't reach from a macro perspective. 7. What is a geographic information system? ..... 85% of the total information is related to geographical location. Information related to geographical location is called geographical information. This kind of information is quite extensive, such as the distribution of cultivated land, forest land, towns and buildings, roads, rivers, coasts, population, hospitals, schools, enterprises and institutions, pipelines, police stations, shops, wells, house numbers, switches, etc. Anything that can be described by "location" belongs to "geographic information". .. how do we manage this information? Geographic Information System (GIS) is a computer software system specialized in managing geographic information, which can not only manage the above information in different categories and at different levels; But also can combine, analyze, recombine and reanalyze them in various ways. It can also query, retrieve, modify, output and update. Geographic information system also has a special "visualization" function, that is, all the information is vividly reproduced on the map or remote sensing photos through the computer screen, and it becomes an information visualization tool, which can clearly and intuitively display the laws and analysis results of information, and at the same time, it can dynamically monitor the changes of "information" on the screen. In a word, Geographic Information System (GIS) can be popularly understood as the "big housekeeper" of information. As can be seen from the above description, the whole geographic information system consists of computer, geographic information system software, spatial database, analytical application model, graphical user interface and system personnel. 8. What is the Global Positioning System (GPS)? ... a system consisting of 25 satellites in six orbital planes, with an altitude of 20 thousand kilometers. This system is used to provide users anywhere on the earth with high-precision position, speed and time information at any time, or to provide users with such information of their neighbors. We know that a photo has no coordinates, and the information in the photo, especially the information in the remote sensing image, needs to be located. Only "information with location" can become geographic information. So how to determine the location of remote sensing photos? There is a convenient and quick means, that is "global satellite" positioning system. The system is completed by 24 GPS satellites in space. Just three can quickly determine your position on the earth. When determining the location, you only need a "satellite locator" the size of a mobile phone. This is much more advanced than traditional measurement and positioning, compass positioning and so on. ... GPS has six main characteristics: ... First, it is all-weather and is not affected by any weather; ..... Second, global coverage (up to 98%); ..... Third, the three-dimensional constant speed timing accuracy is high; ..... Fourth, fast, time-saving and efficient; ..... Fifth, it has a wide range of uses and diverse functions; ..... Sixth, movable positioning. ..... In short, once you have GPS, the vast sky is yours. 9. What is a "digital map"? Usually, the maps we see are based on paper, cloth or other visible objects of real size, and the map contents are drawn or printed on these carriers. Digital maps are stored on the hard disk, floppy disk or magnetic tape of the computer, and the map contents are represented by numbers, which need to be displayed, read, retrieved and analyzed by special computer software. Digital maps can represent much more information than ordinary maps. .. digital map can easily combine and splice the elements of ordinary map in any form to form a new map. Digital maps can be drawn and output at any scale and range. Easy to modify, can greatly shorten the drawing time; It can be easily combined with satellite images, aerial photos and other information sources to generate new maps. New data can be derived from the information recorded in the digital map. For example, the contour lines on the map represent landforms, which are difficult for non-professionals to understand. Using contour lines and elevation points of a digital map, a digital elevation model is generated, and the surface undulation is expressed in digital form, so that the landform can be expressed intuitively and stereoscopically. This is the performance effect that ordinary topographic maps can't achieve. X. What is spatial data? Spatial data refers to the data used to express the position, shape, size and distribution characteristics of spatial entities, which can be used to describe targets from the real world, and has the characteristics of localization, qualitative, time and spatial relationship. Positioning means that all spatial objects have unique spatial positions in the known coordinate system; Qualitative refers to the natural attribute of a space target, which is accompanied by the geographical position of the target; Time refers to the change of space objects with time; Spatial relations are usually expressed by topological relations. Spatial data is a kind of data that uses basic spatial data structures such as points, lines, planes and entities to represent the natural world on which people live. Spatial data is the basic information of digital earth, and most functions of digital earth will be based on spatial data. Nowadays, spatial data has been widely used in various industries and departments of society, such as urban planning, transportation, banking, aerospace and so on. With the development of science and society, people are more and more aware of the importance of spatial data to social and economic development and the improvement of people's living standards, which also accelerates the pace of people's acquisition and application of spatial data. XI。 What is massive data? .. massive data is an adjective used to describe huge and unprecedented massive data. Now many business departments need to operate massive data, for example, the planning department has planning data, the water conservancy department has water conservancy data and the meteorological department has meteorological data. These departments deal with a large amount of data. It includes all kinds of spatial data, report statistics, text, sound, image, hypertext and other environmental and cultural data information. What are the orbits of satellites? The orbit of a satellite can have different names according to its shape. .. 1) circular orbit, elliptical orbit, parabolic orbit, etc. You can imagine them by their names. .. 2) Geostationary orbit .. The turnaround time of a satellite around the earth is equal to the rotation period of the earth. This orbit is called geosynchronous orbit. If the satellite is motionless on the equator from all parts of the ground, this orbit is called geostationary orbit. Geostationary orbit is widely used in meteorological satellites and communication satellites. Because it can observe a specific area for a long time and bring a large area into view. .. 3) Sun synchronous orbit ... Sun synchronous orbit refers to the orbit in which the orbit plane of the satellite rotates in the same direction as the revolution direction of the earth in 1 sidereal year. In sun-synchronous orbit, satellites always pass through the same place in the same direction. So the incident angle of sunlight is almost fixed. ... 4) Quasi-regression orbit ... Regression orbit refers to the orbit that the next point of the satellite passes through the same place every day, and it is called quasi-regression orbit once every n days. Quasi-regression orbit is suitable for covering the whole earth. Thirteen, aerial photography ... photos taken from the aerial platform. 14. Space photography ... photos taken from a spaceship. 15. Bandwidth ... A range of spectral frequencies in a certain band. Sixteen, base map (base map) ... represents the basic map of plane, three-dimensional, geography, politics and cadastre, and there are various types. Basic image information is extracted together with other theme change information. Benefit analysis (Benifi analysis) ... study the special benefits of remote sensing application technology in a special field. 18. Buffer ... An area at a certain distance around a physical entity (such as a point, line or polygon). Cadastral survey ... a record of the nature and scope of land. Generally, it refers to the maps and descriptions that explain the contents of the plots, and the proof of who owns the land ownership. Cadastral information usually includes descriptions of other information about land parcels. 20. Map reference ... refers to a point in an image whose position is known, so that the accurate position and direction of other parts of the image can be determined. 2 1. Contour drawing ... A graph with equal online parameter values. Twenty-two, the universe .. Russian series of satellites. 23, data conversion (data conversion) ... from one image form to another image form of data (infrared band-visible band; Converting pixels into new categories; Changes in image representation; Wait). 24. Data layer ... A set of data that can be used for superposition. Each floor is generally a theme (such as irrigation level, forest type, road, etc. ) and connected to other layers through a common coordinate system. 25. The United States Defense Cartography Agency (DMA) is a United States government agency. Twenty-six, digital terrain model (DTM) ... The terrain of the earth is expressed in digital form, that is, the coordinates and heights are expressed in digital form. Twenty-seven, edge matching (edge matching) ... When two pictures are connected into one picture, the process of eliminating the differences of features and edge representations in adjacent pictures. 28. Features ... Representation of geographical elements, such as points, lines and polygons. Twenty-nine, feature data ... a general term to describe features according to spatial location, attributes and relationships. Such as roads, lakes and railways. Geocoding ... the process of correcting the image, correcting all errors related to the data source, and transforming the image geometry into the required map projection by resampling to square pixels of standard size. 3 1. Geographic reference ... establishes a connection between two kinds of coordinates: the coordinates on a paper map or manuscript and the known real coordinates. 32. A point in the ground-controlled ... system whose position and/or elevation are obtained by ground survey. This point is used to locate map features and associate them. 33. The truth on the ground. The information obtained in the field is aimed at calibrating and/or verifying remote sensing data. 34. Image correction (image correction tin) .. The process of making an image into a plane, which will not eliminate elevation distortion or perspective distortion. 35. Grating overlap ... Match points on two or more overlapping images to correspond to points on the ground. Thirty-six, image resampling in digital image processing for geometric correction technology. Through the interpolation process, the output pixel values are derived as a function of the input pixel values, and the calculated distortions are combined. Nearest neighbor, bilinear interpolation and cubic convolution are commonly used resampling techniques. Image processing) ... includes various processing methods that can be used for photographic data or image data, including image compression, image restoration, image enhancement, preprocessing, quantization, spatial filtering and other image pattern recognition technologies. 38. Map projection) ... a method of representing part or all of the earth's surface on a plane. Mosaic) ... Matching the edges of aerial or aerospace images with overlapping parts to form a continuous image of a part of the earth's surface 40. Multispectral image. More than two images are obtained at the same time, but each image is obtained in a different part of the electromagnetic spectrum. Orthophoto is photography derived from ordinary perspective photography through simple or differential correction. After correction, the image displacement caused by camera tilt and terrain height is eliminated. Panchromatic film A thin film that is sensitive to all wavelengths in the visible spectrum, but not necessarily so uniform. 43. Photogrammetry ... applies the principle of photography to cartography. This is a science to obtain reliable spatial measurement data from images. 44. pixels. A "picture element" is a number corresponding to a digital image data set. Forty-five, point (poin) ... Only x and y coordinates indicate that the geographical area is too small to be displayed as a line or area. 46. Quickly find ... images generated when data is online or transmitted, or immediately after receiving data. This image has not been corrected by computer, but its resolution and clarity can provide visual information for most applications. 47. Correcting the process of converting a network image or network from image coordinates to actual coordinates. Calibration usually involves the calibration and scaling of the grid, so it is necessary to resample the values. 48. Rubber sheet ... Geometrically adjust the map elements and force the digital map to adapt to the specified base map. Spin 2 ... Russian satellite, 2m resolution, orthorectification, panchromatic and digital data. 50. Spin control is a method of generating ground control points from Spin-2 data with low cost and short time, which is used for geometric correction of other satellite data. 5 1. Stereoscopic analysis ... the technology of obtaining stereoscopic information from images (single or paired). 52. Stereo image ... two images in the same area, but taken from different sensor platforms, so that stereoscopic vision can be generated. Stereo orthophoto image. A pair of images using orthophoto, one of which is artificially made by the other original orthophoto. 54. Thermal imaging ... images produced by thermal radiation (infrared or microwave). 55. Triangulation ... Expand horizontal or vertical control points, and use the perspective principle of photography to link the measurement of angle and distance with spatial coordinates in overlapping photography. 56. United States Geological Survey. United States Geological Survey. ) 57. Vector data ... Use points, lines and polygons to represent spatial data. These points, lines and polygons are digitally encoded according to their origins, breakpoints and endpoints. Fifty-eight years old, VTU .. Russian Defense Cartography Bureau.