What symbols are there underground? What do they mean?

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Map knowledge

First of all, the definition of map

A map is a graph of the earth (or planet) on a plane. More precisely, a map is a graphic drawing of natural and social phenomena of the earth (or planet) on a plane with symbols after generalization and selection according to certain mathematical laws. According to the different uses of each specific map, the geographical distribution and relationship of several phenomena are selectively explained. A map is an abbreviation for objects and phenomena on the earth, but it is different from landscapes, photos or pictures on the ground because it has unique characteristics:

1. Special mathematical rules:

As we all know, the surface of the earth is an inextensible surface. When making a map, we must first calculate the surface of the earth on an approximate ellipsoid of revolution, and then draw the ellipsoid of revolution on a plane. This process is solved by the special mathematical law of map projection, which is the basis of forming a map.

2. Specific symbols:

When making a map, we should show everything or phenomena on the surface of the earth according to a certain schema and its prescribed symbols.

3. The method of cartographic generalization:

Another feature of the map is to express the content through cartographic synthesis. Synthesis includes two meanings: selection and generalization. With the reduction of map scale, the capacity of various elements represented on the map also decreases. The minor and minor can be discarded, while the basic and major should be retained and emphasized.

Second, the map scale

A map is a graph drawn on a plane after the surface of the earth is reduced in a certain proportion. Therefore, if you want to know the length of a certain distance on the map, you must know the multiple of the reduced field on the map.

Definition of map scale: the ratio of the length of a section on the map to the actual corresponding length.

The manifestation of map scale:

1. Text scale: directly describe the scale relationship between the map and the field length in words, such as "1 cm stands for 10 km".

2. Fractional scale: the numerator is the distance on the map and the denominator is the distance on the spot. The numerator and denominator are in the same unit, and the numerator is 1, such as "1: 5000".

3. Graphic linear scale: a common scale on the map, which can directly measure the corresponding field distance on the map without mathematical calculation.

4. Oblique scale: Oblique scale is a complex scale with vertical and horizontal divisions, so it is also called complex scale and differential scale.

5. Latitude scale: The above-mentioned linear scale and oblique scale are mainly used for large and medium-scale maps, but on small-scale maps (1: 1 less than 10,000), due to the projection, the length deformation of each latitude (or longitude) is different, so a linear scale cannot be used to summarize the whole map. At this time, a linear scale should be drawn for each latitude (or longitude), which is called latitude scale.

General classification of maps

Maps can be classified according to content, scale, use, drawing area, use mode and age.

According to the content, maps can be divided into two categories: general maps and thematic maps. Ordinary map refers to a map that comprehensively reflects the general characteristics of objects and phenomena on the ground, including various natural geographical elements (topography, water system, vegetation, etc. ) and socio-economic factors (residential areas, administrative divisions, traffic lines, etc.). ). This kind of map can provide necessary information for national economic, cultural and national defense construction, and it is also the base map for drawing thematic maps. Thematic maps, focusing on one or several elements of natural and social phenomena. This kind of maps can be basically summarized into three types, namely, physical geography maps, such as climate maps, geological maps, seismic maps, soil maps, vegetation maps and so on. Social and economic maps, such as economic maps, administrative maps, population distribution maps, production planning maps, etc. ; Historical map.

According to the scale, maps can be divided into large, medium and small scale maps. Maps with a scale greater than or equal to 65438+100000 are large-scale maps, maps with a scale less than or equal to 65438+1000000 are small-scale maps, and maps with a scale greater than 65438+100000 are medium-scale maps. The maps used in our teaching generally belong to small-scale maps. Such as teaching wall charts, atlases, maps, illustrations of teaching materials, etc.

According to the mapping area, it is divided into world map, hemisphere map, mainland and ocean map, regional map, provincial and city map, county and township map.

It is divided into military maps, planning maps, traffic maps, navigation maps, tourist maps, teaching maps, scientific reference maps, etc.

According to the way of use, there are wall charts, table charts and field charts.

According to color, there are monochrome charts and multicolor charts.

Circuit diagram and image diagram according to the form of expression.

In addition, there are globes, square maps, moon maps, star maps and sky maps, and miniature maps and digital maps have appeared in modern maps.

Special map and its application

There are many kinds of common maps, but generally according to certain mathematical rules, all kinds of natural or socio-economic phenomena are represented on a plane in a reduced way with a symbol system, and displayed to people in the form of leaflets or atlases for reading and use. It has become a tool that people often use in their daily work, study and travel, and it is also an important means to learn geography and related sciences and engage in geography teaching. With the rapid development of science and technology and the mutual penetration of multi-disciplines, maps are constantly developing from content to form, from theory to method, from compilation to application, thus forming many unconventional maps or maps copied with special materials, such as audio maps, digital maps, stereoscopic maps (including stereoscopic models, computer-aided three-dimensional perspectives, grid maps, complementary color maps, etc.). ), Braille map, luminous map, non-paper map (including plastic map). These special members of the map family have enriched and developed the theory of cartography, expanded the breadth and depth of map application, and played an important role in national economic construction, national defense construction and daily life.

Stereo map

Maps generally only represent the plane features of the ground. To explain the characteristics of height distribution, it is necessary to add elevation data, or draw contour maps, or indirectly express them by shading. Three-dimensional maps can directly observe the three-dimensional forms of geographical elements such as terrain through intuitive methods or with the help of instruments and equipment. At present, there are many kinds of common three-dimensional maps, such as three-dimensional model, computer-aided three-dimensional perspective, raster map, complementary color map and so on.

Stereo terrain model

Traditional terrain models are usually made of gypsum or sand, stone and soil. This method and material have been used for a long time and are gradually replaced by three-dimensional models made of plastic molds. The three-dimensional map of this new material is light, firm, colorful, high in precision and clearly marked, which is very popular.

Three-dimensional perspective of computer-aided production

This is a new mode of combining computer with traditional map making. On the basis of digitizing the original contour topographic map, it is automatically drawn on the plotter through the automatic drawing software for drawing three-dimensional perspective. Many different three-dimensional perspective stereograms of the same area can be obtained from different perspectives (0-90) and orientations (0-360). The method is simple, the figure is novel, and the terrain features are obvious, but the measurement accuracy is poor. Three-dimensional perspective can not only represent terrain elements, but also be widely used in various thematic maps. It represents the geographical position of geographical phenomena on the plane, and at the same time, it represents the distribution characteristics of thematic elements such as population, environment and socio-economic factors in the form of three-dimensional columns, grids or trends.

Raster map

We can see from the covers of some picture books or ruler patterns used by students that some images are lifelike three-dimensional landscapes or three-dimensional images from a certain angle, that is, grating stereo photo. Some maps also have this function. It uses a dual-lens camera to shoot a three-dimensional model picture or scene from different angles, and then superposes the two images together to obtain multiple groups of strip-shaped image pairs, and then it is covered with a grating film made of plastic, and a virtual three-dimensional image is seen through the grating. At present, due to the lack of imaging clarity and the limitation of photography format and technology, only some smaller maps can be made to show the general situation.

Complementary color map

Complementary color map is based on the actual situation of topography and geographical landscape, and is made by applying the parallax theory of human eyes and the complementary principle of red and green. When people observe a landform or geographical landscape with both eyes at the same time, their images on the left and right retinas are basically the same in size, shape and brightness. Because people's eyes observe the scenery from two different positions and angles, there are differences in the positions of the plane images formed on the retinas of the left and right eyes, that is, the parallax of the human eyes, which will form a complete image with three-dimensional depth after processing in the visual area of the brain. At this time, with the help of the complementary colors of red and green, different landforms and geographical landscapes, such as mountains, rivers, buildings and scenic spots, are printed into overlapping red and green colors, and a three-dimensional map that looks chaotic to the naked eye but vivid with red and green glasses can be obtained. When using the complementary color chart, just wear a pair of special red and green complementary color glasses, that is, one side is red and the other side is green. Due to the color filtering effect of red and green lenses, each eye can only see lines of one color. A three-dimensional scene can be established by reflecting two parallax images to the brain through red and green eyes. Complementary color map can vividly display three-dimensional terrain, which makes people feel vivid and intuitive. Therefore, in geography teaching, students can learn a variety of landforms (such as glaciers, river valleys, karst, loess gullies, coasts, etc.). ) is more intuitive and in-depth, and can also provide tourists with a more comprehensive and intuitive overview of tourist areas.

Audio map

Paper is a common carrier of geographic information. Although the load on the map is considerable through the rational design of patterns and the scientific use of colors, the amount of geographical information that needs to be expressed on the map is much larger, and it is often limited by the width and scale, and only part of the information can be selectively expressed, mainly static geographical landscape and its temporal and spatial distribution characteristics. Too much emphasis on increasing the drawing load sometimes backfires. One of the effective ways to increase the map information capacity and improve the application effect is to change the paper as a single carrier. Therefore, the magnetic tape with high-density recording information and additional devices are combined with the conventional map to form a "sound map". Audio map is designed and made according to the principle that people's audio-visual ability can be improved under the condition of coordinated proportion. According to the research of psychophysics, among human sensory organs, vision transmits information fastest, followed by hearing. If a certain proportion of vision and hearing are mixed, the temporary neural connection established on the cerebral cortex will be supplemented, revised and perfected, and finally a complete concept of objects and images will be formed. Audio map consists of public map, controller, search board and recorder/player accessories. The director is a pointing stick composed of electronic circuits, which can be used to point out the ground symbols on the map and retrieve the descriptions of the ground symbols from the tape. The search pad is made of nylon, with many squares printed on the surface that can be used for map positioning, and there are search grids and extraction electrodes made of conductive resin mixed with offset printing in the interlayer; The recorder appender has the functions of storage, addressing and control, and is controlled by the signal output from the search board. When using the audio map, as long as the map is placed on the retrieval pad and positioned according to the original positioning requirements, when the director points to a characteristic symbol of the map, the retrieval signal output by the director enters the tape recorder attachment through the extraction electrode through the grid in the interlayer of the retrieval pad, and the corresponding explanation content is retrieved from the tape. In this way, while observing the symbol of a certain element on the map, you can also hear the explanation about the element. With the passage of time, vision is staring at a certain ground symbol, but hearing is constantly receiving new content information. At this time, people are in a state of highly concentrated thinking, which is conducive to improving the reading and application effect of maps.

Digital map

Ordinary maps are printed on paper or other materials and can be read and measured directly. Digital map is a special kind of "map", which digitally stores all the information that needs to be represented on the map in the computer without displaying graphics, and then carries out purposeful processing and analysis when using it, and then expresses it with graphics and other forms (profile, hydrological map, etc.). ) or directly provide answer data. Its data comes from all kinds of remote sensing images, general maps and thematic maps. All these information are converted into all kinds of data through special programs, which can be classified, combined, calculated and processed according to users' requirements, and then new maps with different scale series are formed. Because digital maps are fast, accurate, informative, novel and diverse, they are widely used. For example, the traffic map in the form of digital map can display the graphics of the required area in time and adjust the scale according to the resolution, providing ever-changing detailed road information. Another example is the Swiss National Atlas, which can also store all its information on a special 46 floppy disk for readers to call and read on a microcomputer.

Braille map

It is specially used for the blind, and features are displayed with bumps of the same size and different combinations. Many countries have done this, such as the small-scale map of Poland and the large-scale map of the White House compiled by the United States.

Luminous map

Also known as luminous map and fluorescent map, the map content is printed on special fluorescent paper with special color ink and ordinary printing method, and the surface of the map is continuously irradiated with invisible ultraviolet rays in the dark environment to make the content clear and readable. There are many kinds of fluorescent maps, including fluorescent topographic maps and fluorescent charts, which are widely used in military operations or underground projects at night.

Non-paper map

According to the materials that carry the map elements, non-paper maps include plastics (plastic sheets, plastic sheets, pearlescent plastic sheets, etc.). ), silk, polyester, cotton. These maps are generally folding-resistant, wear-resistant, light and not afraid of water, among which polyester-cotton maps are good materials for teaching wall charts, which are more and more loved and adopted by teachers. Transparent polyester plastic sheets in plastic maps can often be used as the second base map of atlas (for example, plastic sheets of administrative areas can be superimposed on various thematic maps for professional analysis) or as a combination of thematic maps (for example, point population maps made of plastic sheets can be superimposed on other population maps for analysis).

The map is a big family. If we introduce maps according to their functions, with the development of national economy and the progress of science and technology, many new varieties have appeared. All these thematic maps, as well as our common general maps, thematic maps and image maps, have great application potential and play an increasingly important role in all walks of life, especially in science, culture, education and other fields.

Pei Xiu, an ancient cartographer in China

Pei Xiu was an outstanding cartographer and geographer in ancient China and an innovator of cartography system. Based on his own research, he creatively put forward "Six-body Cartography", which is of epoch-making significance in the map history of China and occupies an important position in the map history of the world. Some people compare Pei Xiu of China and Ptolemy (about 99- 168), a European cartographer, to two superstars in the history of ancient maps.

Pei Xiu, born in Wenxi, Hedong (now wenxi county, Shaanxi), was born in 223 AD (the fourth year of Huang Chu, Wei Wendi) and died in 27 1 year (the seventh year of Emperor Wu of Jin and Qin Shihuang) at the age of 48. His grandfather Pei Mao was a minister in the Han Dynasty, and his father Pei Qian was a minister in Wei State. Pei Xiu was smart and studious when he was young. In the book "Biography of Jin Ping Mei", he said that he was "learning by heart and learning everything". Because of his bureaucratic family and talent, Emperor Wu of Jin became an "ordinary official", managing the country's household registration land, land tax and maps. At the age of 34, he went to Huainan with Si Mazhao, Emperor Wen of Jin, to conquer Zhuge Dan and give advice to Emperor Wen of Jin. After the pacification of Zhuge Dan, Pei Xiu was made an official order and later entered Luyang Township, increasing the number of households in the city. Because of his "ordinary" position at that time, he was able to get more contact with map materials and consider geographical issues, which laid the foundation for his future reform of map drawing methods.

On the way to March, Pei Xiu inspected the place where the army passed, and recorded the distance of the region, the dangers of mountains and rivers, and the straightness of roads. , and then compare it with the previous figure to check whether there are any errors; The recorded mountains and rivers, ocean currents, Beize, Gujiuzhou, Sixteen States of Jin, counties, cities, border towns, land and water trails, etc. were also textual researched. Through comparative argumentation, Pei Xiu gradually discovered the defects of the map at that time. On the one hand, the place names contained in the map do not match the actual place names. "Book of Jin Pei Xiuchuan" said: "As a local official, the names of mountains and rivers have been changed for a long time, and the words of later generations, or those painted in Xinjiang, are getting darker, so the old articles are picked up, and the doubters are not seen. The famous ones in ancient times and those that are not available now have all made 18 maps of Gong Yu with examples. " It can be seen that Pei Xiu's record of place names in drawing is realistic. On the other hand, when the map is very rough. He said in the preface to Eighteen Pictures of Gong Yu: "... Today's ministers have neither ancient maps nor Xiao He's income, but the maps of the Han Dynasty and its surrounding areas have not been divided, nor have they been verified, and they are not prepared to carry famous mountains and rivers. Although rough, it can't stand on its feet without careful investigation; Or the words of the wilderness are untrue and meaningless. " On the basis of summarizing the previous cartographic experience, Pei Xiu creatively put forward "six-body cartography", that is, six principles that should be followed in drawing maps, which provided a complete specification for future generations to draw maps. He said: "The main body of painting has six aspects: one-day rate, so the degree of debate is also wide;" Looking forward to the next day, so I am in each other's body; Three days on the road, so the number of decisions is also determined; Four days of competition, five days of leaning and six days of straight, these three are different according to local conditions, so they are different. If there is an image but no score, there is no difference between distance and distance; If you have a percentage without certain expectations, although you get it in one corner, you will lose it in another corner; If there is a quasi-hope and no way, it will be applied to the land where mountains and seas are isolated and impassable; If there is a faction in Tao that is not superior, evil and circuitous, then the number of Tao is contrary to the reality of distance and will be inaccurate. So use six references to test. However, the reality of distance depends on speed; The reality of the other party is set in the Tao; The degree of reality depends on the following calculation of evil and straightness. Therefore, although there are steep mountains and huge seas, the return of unique areas and the causes of paradoxes can be determined. If the method of aiming is correct, it is straight and far, and there is nothing to hide. "This passage explains in detail the content and importance of painting six bodies. From the current cartography point of view, "score" is the scale, which is used to determine the distance; "quasi-sight" means orientation, which is used to set the direction; "Reality" means distance, which is used to determine the actual position of each place. In addition, there are competition (taking down the height), square evil (taking an oblique direction) and straight (taking a straight direction), all of which are related to the distance from the ground. It is required that the distance between map elements must be calculated according to the horizontal straight line distance. If we can follow these six standards, combine with reality and adjust measures to local conditions, the map can be drawn accurately. Otherwise, the map drawn without these elements will inevitably have distance error or direction error. Except that I didn't know the latitude and longitude at that time, the current painting method is consistent with what Pei Xiu said in principle. These six drawing principles were first summed up by Pei Xiu more than 1700 years ago, which is an amazing thing.

Pei Xiu's six-body cartography can't be put forward without the wisdom of working people, but his cartography theory and research achievements have greatly surpassed those of his predecessors and erected an indelible monument in the history of map development in China.

Thematic map

A map that highlights and profoundly reflects one or several elements or phenomena, that is, a map that focuses on a certain theme. It is mainly divided into natural maps that reflect various elements or phenomena in nature, socio-economic maps that reflect things or phenomena in human social and economic fields (humanistic maps), and environmental maps that reflect the relationship between human beings and nature.