Small scale maps examples. When are small-scale maps used, and when are large-scale maps used? In Russia, topographic maps have standard numerical scales.

Lecture 2 Rotar M.F.

card is a reduced, generalized image of the Earth's surface, built in a cartographic projection, showing the objects located on it in a certain system of conventional signs.

Topographic plan - an image (model) of a piece of terrain built without taking into account the curvature of the earth's surface.

small plots earth's surface(up to 20 sq. km.) can be considered flat and depicted on a plane in compliance with the similarity of all terrain contours, i.e. in orthogonal projection In orthogonal projection, the projection lines are perpendicular to the projection plane. Let's pass through the points A, B, C, D lines perpendicular to the projection plane P; at their intersection with the plane P get orthogonal projections a, b, c, d corresponding points (Fig. 1.5-b)

Based on the above, we can give the following definition. A topographic plan is a reduced similar model of the earth's surface, obtained by orthogonal (along a plumb line) projection of terrain lines onto a horizontal plane, without taking into account the curvature of the Earth.

Terms and Definitions.

2. Scales of maps and plans. Scale Accuracy

On topographic maps and plans, horizontal projections of terrain lines are depicted, which are called horizontal projections, while the terrain image is reduced.

The degree of linear reduction of the horizontal lines of the terrain when depicted on a plan or map is called scale plan or map.

The scale is expressed as a simple fraction with a numerator equal to one and a denominator showing the degree of reduction in the horizontal alignment of terrain lines when depicted on a map or plan. The larger the scale denominator, the smaller the map and vice versa.

The minimum value that can be seen with the naked eye is a segment of 0.1 mm. This value is called the limiting graphical accuracy. The horizontal spacing of terrain lines corresponding to 0.1 mm on a map or plan is called scale accuracy. So, for example, for scales 1: 500, 1: 1000, 1:25 000, the scale accuracy is 0.05, 0.1, 2.5 m, respectively.

Scale accuracy allows you to solve two important problems:

1) determination of the minimum dimensions of objects and objects of the terrain that are depicted on a given scale, and the sizes of objects that are not depicted on a given scale.

2) setting the scale at which the map should be created so that it depicts objects and terrain objects with predetermined minimum sizes.

3.Classification and purpose topographic maps and plans. Requirements for maps and plans.

The maps depict information about the area, necessary for the most diverse and wide use.

Topographic map- This is a general geographical map showing the totality of the main elements of the area. Topographic maps depict the following groups of terrain elements:

physical and geographical - hydrography, relief, soil and vegetation cover;

socio-economic - settlements, road network, hydraulic and reclamation structures of the border and fences.

General geographical maps of scale 1: 1000 000 and larger are considered topographic. In our country, topographic maps and plans are created on the following scales, which make up the scale range:

Small scale - 1:1000,000, 1:500,000, 1:200,000;

Medium scale - 1:100,000, 1:50,000, 1:25,000;

Large scale - 1: 10,000, 1: 5,000,

Topographic plans - 1:2000, 1:1000, 1:500.

scale series installed in such a way that Firstly so that the cards of this series satisfy all the needs of the national economy and the defense of the country; Secondly the number of scales in it was minimal; thirdly, it was possible to easily move from one scale to another.

Requirements for topographic maps:

Geometric accuracy - the degree to which the location of points on the map corresponds to their location on the earth's surface;

Reliability of the card - the correctness of the information given by the card on a certain date;

Visibility of the map - the possibility of visual perception of spatial forms and, sizes and placement of depicted objects provided by the map;

Readability of the map - filling the map with conventional signs and inscriptions;

The modernity of the map is the correspondence of the map to the current state of scientific and technological progress.

Appointment of topographic maps and plans.

Topographic maps of each of the accepted scales have their own purpose.

So small scale topographic maps are intended for general study of the area in the general design of the national economy, accounting for the resources of the Earth's surface and water spaces, preliminary design of large engineering structures and defense needs.

Medium scale topographic maps differ from small-scale maps in greater detail of the content and higher accuracy of the objects depicted on it. These maps are used in agriculture, in geological exploration, in hydraulic engineering, in the survey and design of railways and roads, pipeline routes, power lines, and forestry.

Large scale maps and plans are intended for the development of master plans for cities and other settlements, engineering networks, for detailed exploration of minerals, for maintaining a land cadastre and land management in built-up and non-built-up areas.

Plans scales 1: 1000 and 1: 500 are also the main plans for accounting for underground utilities.

Any branch of the national economy cannot do without a topographic map or plan. Topographic maps can be on paper or presented as a digital terrain model. DSM is information about the spatial coordinates of a set of points on the earth's surface, combined into a single system according to certain mathematical laws.

4. Cartographic conventional signs.

Conventional signs are graphic symbols used to show the location of objects and phenomena on maps and plans, as well as their qualitative and quantitative characteristics.

Symbols must be:

Good distinguishable among themselves, visual and expressive, i.e., if possible, resemble in a pattern or color the objects of the area that they depict; meaningful, i.e., to give, as far as possible, a complete quantitative and qualitative description of the objects depicted; standard, i.e., if possible, the same in style for topographic maps and plans of different scales; economical, i.e. occupy a minimum place on the map, simple to draw, convenient for their printing reproduction, easy to remember. The style and dimensions of conventional symbols are given in special tables of conventional symbols, which are mandatory for all organizations that create topographic maps and plans. For example, "Symbols for a topographic map at a scale of 1:10000" Classification of conventional signs. Conventional signs are divided into the following groups: large-scale, off-scale, linear and explanatory. Scale signs - cartographic conventions used to depict objects expressed on a map scale. The boundaries of such objects of the terrain are shown, as a rule, with a dotted line, and the area inside the boundaries is indicated by the corresponding conventional signs, called areal.

off-scale signs - cartographic conventions used to depict objects whose areas are not expressed on the scale of a map or plan, but these objects are important, or serve as landmarks and therefore should be depicted on the map.

The smaller the scale of the map, the more objects are depicted on it with off-scale signs. The location of the terrain objects depicted on the map by off-scale signs corresponds to a certain point on these conventional signs.

Linear signs - cartographic conventions used to depict objects of a linear nature, the length of which is expressed on the scale of the map, and the width is off-scale. So, for example, linear signs depict communication and power lines, oil and gas pipelines, railways and other roads on small-scale maps, etc. The geometric axis of the sign corresponds to the location of these objects on the ground.

To make the map more visual and readable, when depicting its elements, use different colors: hydrographic elements and wetlands are shown in blue; woodlands and gardens green; fireproof buildings, highways - red; non-fireproof buildings and improved dirt roads in orange; relief is shown in brown. In addition to conventional signs - are given explanatory captions, that explain the species or genus objects depicted on maps and plans, as well as give their quantitative and qualitative characteristics. Geographical names are also indicated - proper names of geographical objects depicted on the map. These include the names of the people. points, rivers, lakes, tracts, passes and t. d.

Bordering the map.

The border design of the card consists of a set of data that facilitates the use of the card and is placed outside the outer frame of the card. So, above the northern part of the outer frame in the middle of the frame, the nomenclature of the map sheet is written, to the right, in brackets, the name of the largest settlement depicted on this map sheet is indicated. Near the northeast corner, above the outer frame, the neck of the map is indicated. Under the southern part of the outer frame, in the middle, the numerical scale is indicated, below it - the linear scale, the height of the section of the relief by contour lines and the system of heights. To the west of the scale, a diagram of the relative position of the meridians is given, indicating the magnetic declination and convergence of the meridians. To the east of the scale, a laying chart is plotted.

Classification of geographical maps marina3107 wrote in April 7th, 2011

Belyaeva Marina, 2 K., 3 gr.

Geographic map- This is a reduced and generalized image of a spherical earth's surface on a plane using conventional signs, made on a certain scale.

Map classification- this is a system representing a set of cards subdivided (ordered) according to some chosen feature.

Division of maps by scale. The following classification of maps by scale is accepted:
I) plans - I:5 000 and larger;
2) large-scale maps from I:I0000 to I:200000;
3) medium-scale maps - smaller than I:200,000 to I:I,000,000;
4) small-scale maps - smaller than I:I 000 000.
Maps of different scales have different detail and accuracy, different generalization and, often, different meaning. Therefore, the scale of the map makes it possible to judge the features of its content.

Classification of maps by spatial coverage. As the largest division, one can single out maps of the starry sky, then maps depicting a single planet, and, further, maps of the largest planetary structures (for the Earth, these are continents and oceans). After that, the classification can go in two ways: by administrative-territorial division or by natural zoning.
One of the most commonly used classifications is as follows:
star charts;
maps of the planets and the Earth;
hemispheric maps;
maps of continents and oceans;
country maps;
maps of republics, territories, regions, administrative regions;
maps of individual territories (reserves, tourist areas, etc.);
city ​​maps;
maps of urban areas, etc.
To Ocean charts can be further divided into charts of seas, bays, straits, harbors.
In addition to this classification, other subdivisions are also possible, for example, the selection of a group of maps of economic regions covering several administrative units (North-Western economic region, etc.), or maps of large natural regions, such as the European part of Russia, the Far East.

Classification of maps by content. There are two large groups of cards: general geographical and thematic. General geographic maps all geographical elements of the terrain are displayed with equal detail: relief, hydrography, soil and vegetation cover, settlements, economic objects, communication routes, communication lines, borders, etc.
General geographic maps subdivided to topographic(in scale I:I00 000 and larger), survey and topographic(I:200 000 - I:I 000 000) and review(smaller I:I 000 000).

The second large group is thematic, showing the location, relationships and dynamics of natural phenomena, population, economy and culture. Among thematic maps, two main groups are distinguished: maps of natural phenomena and maps of social phenomena.
Maps of natural phenomena cover all components of the natural environment and their combinations. This group includes geological, geophysical, relief maps of the earth's surface and the bottom of the oceans, meteorological and climatic, oceanographic, hydrological (land waters), soil, botanical, zoogeographic, medical-geographical, general physical-geographical, landscape, nature conservation.
Maps of social phenomena include maps of the population, economic, science and culture, public services and health care, political and political-administrative, historical. This group of maps is extensive and varied, it is constantly expanding due to new topics that characterize modern society and economy with all the progressive and negative aspects of its development.
To Each of these divisions contains a large number of different thematic maps. For example, economic maps include maps of industry (in general and for individual types), agriculture, forestry, fisheries, energy, transport and communications, trade and finance, agro-industrial complexes, general economic and economic zoning. It should also be noted maps of border (interdisciplinary) themes, reflecting the close interaction of nature, society and economy. Such are maps of the economic evaluation of natural resources, agro-climatic, engineering-geological and many others. Research at the intersection of different branches of knowledge is a characteristic feature of modern science; this is reflected in the development of maps of interdisciplinary, complex topics.

Classification of cards by purpose. The purpose of the cards is as diverse as the spheres of human activity, but some types of cards stand out quite clearly.
Scientific reference cards designed to carry out scientific research on them and obtain the most detailed, scientifically reliable information.
Cultural, educational and propaganda cards intended for the general public. Their goal is to disseminate knowledge, ideas, and expand the cultural horizons of people. Such cards usually have a bright, simple, intelligible design, they are complemented by diagrams, drawings, poster elements.
Technical cards display the objects and conditions necessary to solve any technical problem. This group includes space navigation, air and sea navigation, road, and some engineering maps.
Educational cards used as visual aids or materials for independent work in the study of geography, geology, history and other disciplines. Allocate cards for elementary, middle, high school.
Tourist cards intended for tourists and vacationers. They depict objects of interest for tourism: historical monuments, reserves, museums, as well as hotels, tourist centers, campsites. The maps are colorful, accompanied by pointers and reference information.

Card types. The type of the map characterizes the breadth of coverage of the topic, the degree of generalization of the mapped phenomena. In modern cartography, it is customary to distinguish three main types of maps: analytical, complex and synthetic.
Analytical cards are called, giving an image of individual phenomena (or even individual properties of phenomena) without connection with other phenomena (properties). An example is maps of air temperature, precipitation, winds, pressure, which are analytical climate maps.
Complex maps combine images of several elements of similar subjects, a set of characteristics of one phenomenon. For example, one map can show both pressure and winds in an area. The combination of two or three phenomena on one map allows you to consider them in a complex, compare, compare, analyze relationships.
Synthetic cards reflect a set of interrelated phenomena as a whole. Such maps lack the characteristics of individual components, but their integral assessment is given. For example, a map of climatic zoning is synthetic, it does not contain specific data on temperatures, precipitation, wind speeds, etc., but there is a general assessment of the climate of selected areas. Synthetic maps are inference maps built on the basis of generalization of data contained in sets of analytical and complex maps.

Geographic atlases. Atlases- these are systematic, integral collections of maps created according to a single program. Like maps, atlases are classified according to spatial coverage, highlighting atlases of the planet (Earth, Moon, Venus), continents and oceans, large geographical regions, states, republics, administrative regions, cities. According to the content, atlases are physical and geographical (geological, climatic, etc.), socio-economic and historical.
Of greatest practical importance is classification of atlases by purpose.
Reference atlases- these are usually general geographical and political-administrative atlases that convey general geographical objects in the most detail: settlements, relief, hydrography, road network. These atlases are particularly detailed in terms of geographical nomenclature and are accompanied by extensive indexes of names.
Comprehensive scientific reference atlases- major cartographic works that provide the most complete, scientifically substantiated and versatile characteristics of the territory. These atlases reflect many components of nature, economy, population and culture, their interrelations and dynamics. Scientific reference atlases can be called cartographic encyclopedias for a given territory.
Popular (local history) atlases intended for the general reader, they are publicly available and addressed to students studying their native land, tourists and local historians, hunters and fishermen. Such atlases are usually accompanied by photographs, drawings, basic reference data on the territory, and a list of historical sights.
Educational atlases focused on serving the educational process at school, in higher educational institutions. The set of maps in watlases, the degree of their detail and the depth of disclosure of the content are in accordance with curricula(for example, atlases on geography, history for 5, 6 and other classes).
Tourist and road atlases designed to meet the needs of tourists, athletes, motorists, travelers. They depict in detail tourist sites, networks of automobile and railways, pedestrian, water, automobile routes.

2.1. Topographic map elements

Topographic map - a detailed large-scale general geographical map reflecting the location and properties of the main natural and socio-economic objects, making it possible to determine their planned and altitude position.

Topographic maps are created mainly on the basis of:

• processing of aerial photographs of the territory;
• by direct measurements and surveys of terrain objects;
• cartographic methods with already available plans and maps of large scales.

Like any other geographical map, a topographic map is a reduced, generalized and figurative-sign image of the area. It is created according to certain mathematical laws. These laws minimize the distortions that inevitably arise when the surface of the earth's ellipsoid is transferred to a plane, and, at the same time, ensure its maximum accuracy. The study and compilation of maps require an analytical approach, the division of maps into its constituent elements, the ability to understand the meaning, meaning and function of each element, and to see the connection between them.

Map elements (components) include:

• cartographic image;
• mathematical basis;
• legend
• auxiliary equipment;
• Additional information.

The main element of any geographical map is a cartographic image - a set of information about natural or socio-economic objects and phenomena, their location, properties, connections, development, etc. Topographic maps depict water bodies, relief, vegetation, soils, settlements, communication routes and means of communication, some objects of industry, agriculture, culture, etc.
Mathematical basis topographic map - a set of elements that determine the mathematical relationship between the real surface of the Earth and a flat cartographic image. It reflects the geometric laws of map construction and the geometric properties of the image, provides the ability to measure coordinates, plot objects by coordinates, fairly accurate cartometric determinations of lengths, areas, volumes, angles, etc. Due to this, a map is sometimes called a graph-mathematical model of the world.

The mathematical basis is:

• map projection;
• coordinate grids (geographical, rectangular and others);
• scale;
• geodetic substantiation (strong points);
• layout, i.e. placement of all elements of the map within its frame.

kata scale can have three types: numerical, graphic (linear) and explanatory label (named scale). The scale of the map determines the degree of detail with which a cartographic image can be plotted. Map scales will be discussed in more detail in Topic 5.
Map grid represents the image of the degree grid of the Earth on the map. The type of grid depends on the projection in which the map is drawn. On topographic maps of scales 1:1,000,000 and 1:500,000, meridians look like straight lines converging at a certain point, and parallels look like arcs of eccentric circles. On topographic maps of a larger scale, only two parallels and two meridians (frame) are applied, limiting the cartographic image. Instead of a cartographic grid, a coordinate (kilometer) grid is applied to large-scale topographic maps, which has a mathematical relationship with the degree grid of the Earth.
card frame name one or more lines bounding the map.
To strong points include: astronomical points, triangulation points, polygonometry points and leveling marks. Control points serve as a geodetic basis for surveying and compiling topographic maps.

2.2. Topographic map properties

Topographic maps have the following properties: visibility, measurability, reliability, modernity, geographical correspondence, geometric accuracy, content completeness.
Among the properties of a topographic map, one should highlight visibility and measurability . The visibility of the map provides a visual perception of the image of the earth's surface or its individual sections, their characteristic features and features. Measurability allows you to use the map to obtain quantitative characteristics of the objects depicted on it by measurements.

Visibility and measurability are provided by:

a mathematically defined relationship between multidimensional objects environment and their flat cartographic representation. This connection is conveyed using a map projection;

the degree of reduction in the size of the depicted objects, which depends on the scale;

highlighting typical terrain features by means of cartographic generalization;

the use of cartographic (topographic) conventional signs to depict the earth's surface.

To ensure a high degree of measurability, the map must have sufficient geometric accuracy for specific purposes, which means the correspondence of the location, shape and size of objects on the map and in reality. The smaller the depicted area of ​​the earth's surface while maintaining the size of the map, the higher its geometric accuracy.
The card must be credible, i.e., the information that makes up its content on a certain date must be correct, must also be contemporary, correspond to the current state of the objects depicted on it.
An important property of a topographic map is completeness content, which includes the volume of information contained in it, their versatility.

2.3. Classification of topographic maps by scale

All domestic topographic maps, depending on their scale, are conditionally divided into three groups:

• small scale maps (scales from 1:200,000 to 1:1,000,000), as a rule, are used for general study of the area in the development of projects and plans for the development of the national economy; for preliminary design of large engineering structures; as well as for taking into account the natural resources of the surface of the earth and water spaces.
• Medium scale maps (1:25,000, 1:50,000 and 1:100,000) are intermediate between small-scale and large-scale. The high accuracy with which all terrain objects are depicted on maps of a given scale makes it possible to widely use them for various purposes: in the national economy in the construction of various structures; for making calculations; for geological prospecting, land management, etc.
• large scale cards (1:5,000 and 1:10,000) are widely used in industry and public utilities; when conducting detailed geological exploration of mineral deposits; when designing transport hubs and structures. Large-scale maps play an important role in military affairs.

2.4. Topographic plan

Topographic plan - a large-scale drawing depicting in conventional symbols on a plane (on a scale of 1:10,000 and larger) a small area of ​​the earth's surface, built without taking into account the curvature of the level surface and maintaining a constant scale at any point and in all directions. A topographic plan has all the properties of a topographic map and is its special case.

2.5. Topographic map projections

When depicting large areas of the earth's surface, the projection is made on the level surface of the Earth, in relation to which the plumb lines are normals.

map projection - method of imaging on a surface plane the globe when making maps.

It is impossible to develop a spherical surface on a plane without folds and breaks. For this reason, distortions of lengths, angles and areas are inevitable on maps. Only in some projections, the equality of angles is preserved, but because of this, the lengths and areas are significantly distorted, or the equality of areas is preserved, but the angles and lengths are significantly distorted.

Projections of topographic maps at a scale of 1:500,000 and larger

Most countries of the world, including Ukraine, use conformal (conformal) projections to compile topographic maps, preserving the equality of angles between the directions on the map and on the ground. Swiss, German and Russian mathematician Leonhard Euler in 1777 developed the theory of conformal image of a ball on a plane, and the famous German mathematician Johann Carl Friedrich Gauss in 1822 substantiated the general theory of conformal image and used conformal flat rectangular coordinates when processing triangulation (method of creating a network of control geodetic points). Gauss applied a double transition: from an ellipsoid to a ball, and then from a ball to a plane. The German geodesist Johannes Heinrich Louis Krüger developed a method for solving conditional equations arising in triangulation and a mathematical apparatus for the conformal projection of an ellipsoid onto a plane, called the Gauss-Krüger projection.
In 1927, the famous Russian geodesist, Professor Nikolai Georgievich Kell, was the first in the USSR to apply the Gaussian coordinate system in Kuzbass, and on his initiative, since 1928, this system was adopted as a single system for the USSR. To calculate the coordinates of Gauss in the USSR, the formulas of Professor Feodosy Nikolaevich Krasovsky were used, which are more accurate and more convenient than Kruger's formulas. Therefore, in the USSR there was no reason to give the Gaussian projection the name "Gauss-Kruger".
Geometric entity This projection can be represented as follows. The entire terrestrial ellipsoid is divided into zones and maps are made for each zone separately. At the same time, the dimensions of the zones are set so that each of them can be deployed into a plane, that is, depicted on a map, with virtually no noticeable distortion.
To obtain a cartographic grid and draw up a map in the Gaussian projection, the surface of the earth's ellipsoid is divided along the meridians into 60 zones of 6 ° each (Fig. 2.1).

Rice. 2.1. The division of the Earth's surface into six-degree zones

To imagine how the image of zones is obtained on a plane, imagine a cylinder that touches the axial meridian of one of the zones of the globe (Fig. 2.2).

Rice. 2.2. Zone projection onto a cylinder tangent to the Earth's ellipsoid along the axial meridian

According to the laws of mathematics, we project the zone onto the lateral surface of the cylinder so that the property of the equiangularity of the image is preserved (the equality of all angles on the surface of the cylinder to their magnitude on the globe). Then we project all other zones, one next to the other, onto the side surface of the cylinder.

Rice. 2.3. Image of zones of the earth's ellipsoid

Further cutting the cylinder along the generatrix AA1 or BB1 and turning its side surface into a plane, we obtain an image of the earth's surface on a plane in the form of separate zones (Fig. 2.3).
The axial meridian and the equator of each zone are depicted as straight lines perpendicular to each other. All axial meridians of the zones are depicted without length distortion and maintain the scale throughout their entire length. The remaining meridians in each zone are depicted in the projection by curved lines, therefore they are longer than the axial meridian, i.e. distorted. All parallels are also shown as curved lines with some distortion. Line length distortions increase with distance from the central meridian to the east or west and become the largest at the edges of the zone, reaching a value of the order of 1/1000 of the line length measured on the map. For example, if along the axial meridian, where there is no distortion, the scale is 500 m in 1 cm, then at the edge of the zone it will be 499.5 m in 1 cm.
It follows that topographic maps are distorted and have a variable scale. However, these distortions when measured on a map are very small, and therefore it is believed that the scale of any topographic map for all its sections is constant.
For surveys at a scale of 1:25,000 and larger, the use of 3 degree and even narrower zones is allowed. The overlap of zones is taken 30" to the east and 7", 5 to the west of the axial meridian.

The main properties of the Gaussian projection:

the axial meridian is depicted without distortion;

the projection of the axial meridian and the projection of the equator are straight lines perpendicular to each other;

the remaining meridians and parallels are depicted by complex curved lines;

in the projection, the similarity of small figures is preserved;

in projection, horizontal angles and directions are preserved in the image and terrain.

Projection of a topographic map at a scale of 1:1,000,000

Projection of a topographic map at a scale of 1:1,000,000 - modified polyconic projection, accepted as international. Its main characteristics are: the projection of the earth's surface covered by a map sheet is carried out on a separate plane; parallels are represented by arcs of circles, and meridians by straight lines.
To create topographic maps of the USA and the countries of the North Atlantic Alliance, Universal Transverse Mercator, or UTM. In its final form, the UTM system uses 60 zones, each 6 degrees longitude. Each zone is located from 80º S. up to 84º N The reason for the asymmetry is that 80º S. passes very well in the southern ocean, southern South America, Africa and Australia, but it is necessary to climb to 84º N to reach the north of Greenland. Zones are counted starting from 180º, with increasing numbers to the west. Together, these zones cover almost the entire planet, excluding only the Arctic Ocean and North and Central Antarctica in the south.
The UTM system does not use a "standard" based on the transverse Mercator projection - the tangent. Instead, it is used secant, which has two section lines located approximately 180 kilometers on either side of the central meridian. Map zones in the UTM projection differ from each other not only in the positions of their central meridians and distortion lines, but also in the earth model they use. The official definition of the UTM system defines five other spheroids for use in various zones. All UTM zones in the United States are based on the Clarke 1866 spheroid.

Questions and tasks for self-control

1. Give definitions: "Topography", "Geodesy", "Topographic map".
2. What are the sciences of topography? Explain this relationship with examples.
3. How are topographic maps created?
4. What is the purpose of topographic maps?
5. What is the difference topographic plan from a topographic map?
6. What are the elements of a map?
7. Give a description of each element of the topographic map.
8. What are the parallels and meridians on topographic maps?
9. What elements determine the mathematical basis of a topographic map? Give a brief description of each element.
10. What are the properties of topographic maps? Give a brief description of each property.
11. On what surface are images of large areas of the Earth projected?
12. Define a map projection.
13. What distortions can be formed when a spherical surface is deployed on a plane?
14. What projections are used by most countries of the world to compile topographic maps?
15. What is the geometric essence of the construction of the Gaussian projection?
16. Show on the drawing how a six-degree zone is projected from the earth's ellipsoid to a cylinder.
17. How are the meridians, parallels, and equator drawn in the six-degree Gaussian zone?
18. How does the nature of distortion change in the six-degree Gaussian zone?
19. Can the scale of a topographic map be considered constant?
20. In what projection is the topographic map made at a scale of 1:1,000,000?
21. What map projection is used to create topographic maps in the United States, and how is it different from the Gaussian projection?
    

Maps are divided into groups according to a number of characteristics - scale, subject, territorial coverage, projection, etc.

Simple ones cover maps of the surface of the earth, hemispheres, continents, in terms of scale - large-scale (1/100000 and cr.) Medium-scale (1/200000.1/500 thousand 1/1 million) small-scale (1/1 million and bl).

Topographic maps and plans - purpose - scientific and reference educational, marine navigation, road, cadastral, tourist. Topographic maps and plans have a multi-purpose purpose, so the elements of the terrain are shown on them with the same detail.

Large-scale maps are essential because they provide the primary information used in the compilation of medium- and small-scale maps. The most common of these are topographic maps at a scale larger than 1:250,000.

On modern topographic maps, relief is usually shown using isogypses, or contour lines that connect points that have the same height above zero level (usually sea level). The combination of such lines gives a very expressive picture of the relief of the earth's surface and allows you to determine the following characteristics: the angle of inclination, slope profile and relative elevations. In addition to the image of the relief, topographic maps contain another useful information. Usually they show highways, settlements, political and administrative borders. Kit additional information(for example, the distribution of forests, swamps, loose sandy massifs, etc.) depends on the purpose of the maps and the characteristic features of the area.

Both large-scale topographic and medium-scale maps are usually produced in sets, each of which meets certain requirements. Most of the medium-scale ones are published for the needs of regional planning or navigation. The medium-scale International Map of the World and aeronautical charts of the USA are distinguished by the greatest territorial coverage. Both sets of maps are produced in 1:1,000,000 scale, the most common for medium scale maps. When preparing the International Map of the World, each country issues maps to its territory prepared in accordance with the given general requirements. This work is coordinated by the UN, but many of the maps are outdated and others are not yet complete. The content of the International Map of the World basically corresponds to the content of topographic maps, but is more generalized. The same applies to aeronautical charts of the world, but most of the sheets of these charts have an additional special load. Aeronautical charts cover the entire land. On a medium scale, some nautical or hydrographic charts are also compiled, on which Special attention is given to the image of reservoirs and the coastline. Some administrative and road maps also have a medium scale. Small-scale, or survey, maps. On the maps small scale the entire surface of the globe or a significant part of it is shown. It is difficult to draw a precise line between small and medium scale maps, but the 1:10,000,000 scale definitely applies to overview maps. Most atlas maps are on a small scale, and thematically they can be very different. Almost all the above indicated groups of objects can also be reflected on small-scale maps, provided that the information is sufficiently generalized. In addition, maps of the distribution of various languages, religions, crops, climates, etc. are compiled on a small scale. As an illustrative example of special small-scale maps, well known to millions of people, one can point to weather maps.

Animated and computer cards. For animated maps that can be projected onto a TV screen, the fourth coordinate is introduced - time, which allows you to trace the dynamics of the mapped object. Computer cartography has now reached such a stage of development that almost all operations can be performed in digital form. As a result, it is much easier to make all kinds of corrections and clarifications. This method of creating maps of any type and scale, including cartoon maps, is designated by the special term "geographic information systems" (GIS).

13. Elements of a general geographical map

On topographic maps and plans, various objects of the area are depicted: contours settlements, gardens, kitchen gardens, rivers, lakes. The totality of these objects is called a situation. The situation is depicted by conventional signs. Conventional signs are divided into 5 groups: areal, linear, off-scale, explanatory, special. Areal conventional signs are used to fill in the areas of objects of the direction: arable land, forests, lakes, meadows - they consist of a dotted line of the boundary of the object and fill in its images or conditional coloring. Show objects of a linear nature of the river road, the length of which is expressed in a given scale. On conditional images are given various characteristics objects. Off-scale conventional signs are used to depict objects whose dimensions are not expressed in the given scale of the map or plan. They define the position, but not the dimensions. Explanatory conventional signs are digital and alphabetic inscriptions characterizing objects: direction, depth and speed of river flow. They are put down on the main areal linear off-scale signs. Special conventional signs are established by the relevant departments of the sectors of the national economy; they are used to draw up special maps and plans for this industry. To give a map or plan clarity, colors are used to depict various elements, for rivers, lakes - blue, highways - red.

The content of the article

MAP, a reduced generalized image of the surface of the Earth (or part of it) on a plane. Man has been creating maps since ancient times, trying to visualize the relative position of various parts of land and seas. A collection of maps, usually bound together, is called an atlas (a term coined by the Flemish Renaissance cartographer Gerardus Mercator).

A ball (sphere) with a cartographic image of the Earth applied to its surface is called a globe. This is the most accurate representation of the earth's surface. On all maps that give an image of a ball on a plane, there are certain distortions that cannot be eliminated. Nevertheless, maps have certain advantages over the globe. For example, a map of the world allows you to look at the entire earth's surface (i.e., its image), while on a globe from one point you can see no more than half of the globe; therefore, maps are more convenient when considering the entire surface of the Earth. On the map, in addition, it is much easier than on the globe to measure angles and directions. At present, globes are rarely used for navigational purposes. The image on a spherical surface of territories that do not exceed the size of a subcontinent does not provide practically any advantages, therefore, in such cases, maps are used, rather than segments of the globe. Moreover, maps are much easier to make, transport and store (although some of these difficulties can be overcome by using inflatable globes).

MAIN FEATURES OF THE CARDS

With all the amazing variety of existing maps, most of them have some common features. Even contour maps, which are as unloaded as possible so that students can apply additional information on them of their choice, usually have a degree grid of coordinates, a scale, and basic elements (for example, coastlines). In addition, inscriptions and symbols are usually applied to the cards, and a legend is attached to them.

coordinate grid

is a system of mutually intersecting lines indicating latitude and longitude on a map or globe surface. Latitude lines run east-west parallel to the equator (which has a latitude of 0°); the latitude of the poles is considered to be 90° (North latitude for the North Pole and South latitude for the South Pole). Since these lines do not intersect and are mutually parallel, they are also called parallels. Of these, only the equator is the largest circle (the plane bounded by this line, passing through the center of the Earth, cuts the globe in half). The remaining parallels are circles, the length of which naturally decreases with distance from the equator. All lines of longitude - meridians - are halves of a large circle, converging at the poles. The meridians run in a north-south direction, from pole to pole; they count the angular distance from the initial meridian, denoted as 0 ° longitude, to the east and west to 180 ° (at the same time, longitudes that are measured in the east direction are indicated by the letters “east”, and in the west - “w. etc.") . Unlike the equator, which is equidistant from the poles along its entire length and, in this sense, is a “natural” reference point in determining latitude, the initial meridian from which longitude is measured is chosen arbitrarily. In accordance with international agreement, the meridian of the Greenwich Astronomical Observatory (now located in London) is taken as the origin of coordinates (0 ° longitude). However, before this agreement was reached, some cartographers used as the initial meridians of the Canary or Azores, Paris, Philadelphia, Rome, Tokyo, Pulkovo, etc.

On the surface of the globe, the lines of parallels and meridians intersect at an angle of 90°; as for maps, such a ratio is preserved on them only in some cases. Both on maps and on globes, a certain system of meridians and parallels (drawn through 5 °, 10 °, 15 ° or 30 °) is usually applied. In addition to this, maps and globes show the Northern Tropic, or Tropic of Cancer (23 1/2 ° N), the Southern Tropic, or Tropic of Capricorn (23 1/2 ° S), the Arctic Circle ( 66 1/2°N) and the Antarctic Circle (66 1/2°S). International Date Lines are often also shown on charts, which generally coincide with 180° longitude.

Scale

cards can be numerical (a ratio of numbers or a fraction, for example, 1:25,000 or 1/25,000); verbal or linear (graphic). In the example above, a unit of length on the map corresponds to 25,000 such units on the ground. The same ratio can be expressed by the words: "1 cm is equal to 250 m" or, even more briefly: "250 m in 1 cm". In some countries that traditionally use non-metric measures of length (USA, etc.), the scale is expressed in inches, feet and miles, for example, 1:63 360 or "1 mile in 1 inch". The linear scale is depicted as a line with divisions plotted at certain intervals, against which the corresponding distances on the earth's surface are indicated. The graphical representation of scale has certain advantages over the other two ways of expressing it. In particular, if the size of the map changes when it is copied or projected onto a screen, then only the graphical scale, which changes along with the entire map, remains correct. Sometimes, in addition to the length scale, the area scale is also used. Globes may use any of the above scale designations.

Basic elements and conventional cartographic signs.

The geographic base elements include the image of the coastline, watercourses, political boundaries, etc., which create a base against which the spatial distribution of the displayed phenomenon is shown. When compiling maps, many conventional signs are used, which are divided into several categories: off-scale, or point, used to depict "point" objects or such, scale which cannot be expressed on the map (for example, to show settlements - dots or circles, the size of which indicates a certain population); linear for objects of a linear nature, preserving the similarity of the outlines of the object (for example, the image of a permanent watercourse in the form of a line, the thickness of which increases downstream); areal, used to fill in the areas of objects that are expressed at the scale of the map (for example, hatching or filling with color to show the distribution of forests). These three classes of signs can be further subdivided according to whether the objects they represent are imaginary (for example, political boundaries) or real (roads); whether the signs themselves are homogeneous (points on the map, each of which corresponds to a certain number of inhabitants) or differentially representing the quantitative characteristics of objects (image of cities using circles of different sizes, corresponding to the population); whether they give a qualitative characteristic of the object (for example, the presence of a swamp) or contain quantitative information (for example, population density - the number of people per unit area).

The purpose of the legend is to inform the reader about the meaning of the symbols used. In old maps, the legend was placed in an elaborately ornamented frame in the form of a scroll, and now it is in a strict rectangular frame.

As an example, the legend to the geographical maps contained in the Encyclopedia Around the World is given.

Inscriptions and geographical names on maps.

In the past, all the inscriptions were applied by hand, which gave an individual character to each map, but now cartographers, as a rule, choose one of the standard fonts that best suits the nature of the depicted objects. Some types of fonts are traditionally used for certain groups of objects, for example, rivers, lakes, seas are usually in italics, and land features are indicated in roman type. The size of the letters depends on the significance (or size) of the object. Distances between letters and words in names can vary widely depending on the area or extent of a given object on the map.

The font design of the map includes a heading that reflects the content of the map and the territory to which it refers; for this, the largest font is used. A special place is occupied by geographical names, the selection and number of which depend on the purpose of the map (for example, a city plan contains many street names, and vegetation maps contain only a few of the most necessary names). It is customary to indicate the publishing organization, year of publication, sources used. The map is accompanied by a legend, in which the symbols are deciphered, and sometimes with notes.

Map Orientation

in relation to the cardinal points is determined by the lines of the cartographic grid within the frame of the map and represents an essential element of its layout. In the Middle Ages, both in Europe and in the Arab countries, maps were drawn in such a way that the east was located at the top (the term "orientation" itself comes from the Latin word oriens - east). AT modern maps north is usually at the top of the map, although deviations from this rule are sometimes allowed. Reading a map, especially in the field, is greatly facilitated by its correct orientation relative to objects and directions on the ground. To indicate the cardinal points, a compass card is sometimes depicted on the map, but more often it is just an arrow pointing north.

TYPES OF CARD

Maps are divided into groups according to a number of characteristics - scale, subject, territorial coverage, projection, etc. However, any properly carried out classification must take into account at least the first two features. In the United States, three groups are distinguished by scale: large-scale maps (including topographic maps), medium-scale maps, and small-scale maps, or survey maps.

Large scale maps

are basic because they provide the primary information used in the preparation of maps of medium and small scales. The most common of these are topographic maps at a scale larger than 1:250,000.

On modern topographic maps, relief is usually shown using isogypses, or contour lines that connect points that have the same height above zero level (usually sea level). The combination of such lines gives a very expressive picture of the relief of the earth's surface and allows you to determine the following characteristics: the angle of inclination, slope profile and relative elevations. In addition to the image of the relief, topographic maps contain other useful information. Usually they show highways, settlements, political and administrative borders. A set of additional information (for example, the distribution of forests, swamps, loose sandy massifs, etc.) depends on the purpose of the maps and the characteristic features of the area.

No country in need of an assessment of its natural resources can do without topographic surveys, which are greatly facilitated by the use of aerial photographs. Nevertheless, there are still no topographic maps for many regions of the globe, which are so necessary for engineering purposes. Successes in solving this problem were achieved with the help of the so-called. orthophotomap. Orthophotomaps are based on computer-processed planned aerial photographs with increased color brightness and contour lines, boundaries, place names, etc. applied to them. Orthophotomaps and satellite images with topographic load elements raised on them are much less labor-intensive to manufacture than traditional topographic maps. Many thematic large-scale maps—geological, soil, vegetation, and land use—use topographic maps as a basis upon which a special load is applied. Other specialized large-scale maps, such as cadastral maps or city plans, may not have a topographic basis. Usually, on such maps, the relief is either not shown at all, or is depicted very schematically.

Medium scale maps.

Both large-scale topographic and medium-scale maps are usually produced in sets, each of which meets certain requirements. Most of the medium-scale ones are published for the needs of regional planning or navigation. The medium-scale International Map of the World and aeronautical charts of the USA are distinguished by the greatest territorial coverage. Both sets of maps are produced in 1:1,000,000 scale, the most common for medium scale maps. When preparing the International Map of the World, each country issues maps for its territory prepared in accordance with the given general requirements. This work is coordinated by the UN, but many of the maps are outdated and others are not yet complete. The content of the International Map of the World basically corresponds to the content of topographic maps, but is more generalized. The same applies to aeronautical charts of the world, but most of the sheets of these charts have an additional special load. Aeronautical charts cover the entire land. Some nautical or hydrographic charts are also drawn up on a medium scale, in which special attention is paid to the depiction of bodies of water and coastlines. Some administrative and road maps are also medium scale.

Small-scale, or survey, maps.

Small-scale maps show the entire surface of the globe or a significant part of it. It is difficult to draw a precise line between small and medium scale maps, but the 1:10,000,000 scale definitely applies to overview maps. Most atlas maps are on a small scale, and thematically they can be very different. Almost all the above indicated groups of objects can also be reflected on small-scale maps, provided that the information is sufficiently generalized. In addition, maps of the distribution of various languages, religions, crops, climates, etc. are compiled on a small scale. As an illustrative example of special small-scale maps, well known to millions of people, one can point to weather maps.

Animated and computer cards.

For cartoon cards that can be projected onto a TV screen, the fourth coordinate is entered - time , allowing you to follow the dynamics mapped object . Computer cartography has now reached such a stage of development that almost all operations can be performed in digital form. As a result, it is much easier to make all kinds of corrections and clarifications. This method of creating maps of any type and scale, including cartoon maps, is designated by the special term "geographic information systems" (GIS).

MAIN TYPES OF PROJECTIONS

A map projection is a way of displaying the spherical surface of the globe on a plane. The associated image transformation inevitably leads to distortion. However, some characteristics of the cartographic grid applied to the surface of the globe can be stored on the map at the expense of other characteristics that will be distorted.

On the globe, all parallels and meridians intersect at right angles. A projection in which this property is preserved is called conformal, or conformal. In this case, the shape of areal objects is preserved, but the relative sizes change from place to place. With another method of transformation, it is possible to preserve the correct ratio of areas (corresponding to the original surface of the globe), but in these cases, distortion of the angles of intersection of the meridians and parallels is observed; right angles are preserved only in a limited area. Projections that maintain the correct ratio of the areas of individual cells of the degree grid are called equal; they are characterized by a greater or lesser violation of the similarity of the figures. The correct transfer of the configuration of objects, as well as the correct transfer of areas, are of great importance, especially if we are talking about small scale overview maps. However, both of these characteristics cannot be combined on the same map: there is no projection that would be both equal-angle and equal-area. In addition, the correct display of distances and directions is very important. To some extent, this can be achieved by using certain projections.

Map projections can be classified according to the type of auxiliary geometric surface that can be used in its construction. Let's take a transparent globe with lines of meridians and parallels drawn on its surface and a point source of light. We can enclose a globe (with a light source located in the center of the ball) in a cylinder. In this case, the degree grid is projected onto the surface of the cylinder, which can then be deployed on a plane. The cylinder can be tangent and touch the globe only along one line (for example, the equator), or it can be secant. In the latter case, the surfaces of the sphere and cylinder will coincide along two lines (for example, along 45 ° N and 45 ° S), and only along these lines the correct scale is preserved in this projection. By changing the position of the light source with respect to the surface of the ball, various projections of the cartographic grid onto the surface of a cylinder or other geometric figure can be obtained.

One such figure traditionally used in map projections is the cone. As in the previous case, the cone can touch the ball, or it can cut it. The lines along which these figures touch or cut one another (usually these are certain parallels) maintain the correct scale and are standard parallels. To reduce distortion, a series of truncated cones can be used instead of a single cone; in this case, the correct transfer of scales along a number of standard parallels will be achieved.

In the cases considered, a development on the plane of the cylinder or cone is necessary, but, of course, it is also possible to directly project the surface of the ball onto the plane. In this case, the plane can touch the ball at one point or cut it; in the latter case, the surfaces of the sphere and the plane will coincide along the line of the circle. This transformation of the degree grid is called the azimuthal projection; in it, the true scale is preserved only at the point of contact or at the line of intersection of the plane and the sphere. The configuration of the resulting grid on the projection depends on the position of the light source.

In accordance with the geometric figures used in the construction of the considered projections, the latter are called cylindrical (or rectangular), conic and azimuthal. In addition to those indicated, other transformations of the degree grid are possible, which are not reducible to these simple geometric shapes, but having a mathematical justification; they are usually called arbitrary. Many projections have been developed at various times, but only a few of them have come into widespread use. The task of the cartographer is to choose the projection that best suits the tasks of this map.

A distinctive feature of the stereographic projection is that all objects that are circles on the earth's surface are also depicted on the map as circles or, in some special cases, as straight lines. It is due to this property that the stereographic projection, invented in ancient times, is so widely used now, for example, to show the propagation of radio waves, etc.

The Mercator projection is conformal. Any straight line that intersects all meridians at the same angle on the earth's surface is transmitted in this projection by a straight line, which is called a loxodrome. This remarkable property makes the Mercator projection very useful for navigation charts. Unfortunately, this projection is often misused to show areas such as global population distribution, crops, and so on.

In such cases, it is most appropriate to choose equal projections, for example, a sinusoidal one. This projection, one of many developed for world maps, has a certain defect - both poles on it are located on ledges, and the areas adjacent to them turn out to be significantly deformed. On other maps of the world using equal-area projections, the poles are depicted as a straight line of various lengths (in cylindrical projections it is equal to the equator, in the Eckert IV projection - half the length of the equator, in the flat polar projection - a third of the equator), or even in the form of an arc (Mollweide projection ). The characteristics of some projections are given in the table ( see below). The list of projections placed in the table is far from complete and does not include, for example, polar equidistant and polar equidistant (both azimuthal), as well as some projections that allow you to most accurately reproduce the surface of the globe, for example, orthographic.

One of the most convenient projections, gnomonic, is unique in that any great circle of a sphere (and an arc of a great circle) is represented as a straight line in it. Since the arcs of great circles are the lines of the shortest distances on the map, then on a small-scale map drawn up in such a projection, one can easily find (by a ruler) shortcuts between two points; however, it must be borne in mind what the great circle arc does not correspond to the constant direction measured by the compass. As with other azimuthal projections, in the gnomonic projection the image can be projected onto a plane tangent to the surface of the ball at any point, such as the pole or the equator, but the territorial coverage of such maps is very limited.

The equal area projection of Bonn is more suitable for depicting areas that are elongated in the meridional direction. If the mapped area is elongated in latitude, then the Lambert conformal conic projection is preferable for it. The polyconic projection is neither conformal nor equal area, but for small areas it gives little distortion; it is in this projection that the series of maps prepared by the US Geological, Surveying and Cartographic Service, as well as (with minor changes) the International Map of the World, are compiled. Another equal-area projection, developed for survey maps, combines the features of a sinusoidal (when transferring equatorial regions) and pseudocylindrical Mollweide projections (in polar regions). As in a number of other equal-area projections, the image in it can be given with breaks or in a compressed form.

Discontinuities arise if not one average (rectilinear) meridian is chosen, but several, and for each of them a part of the degree grid is built. An extreme case is the image of the entire surface of the globe in the form of segments of the globe. Maps in this projection also use a "compressed" image; compression is achieved due to the fact that parts of the image that are not needed for a given map (for example, water areas for a land cover map) are “cut out”, and the remaining ones are brought together; this makes it possible to use a larger scale while maintaining the same sheet area.

MAPPING METHODS

Once a projection has been chosen and the corresponding grid has been drawn, one can begin to draw up the basis and prepare the information that determines the content of the map. At the same time, aerial photographs are often used for large-scale maps. Theoretically, a planned aerial photograph contains all the elements of the landscape that can be shown on a large-scale map. Moreover, having photographs partially overlapping each other, it is possible to build relief maps in contour lines; this requires a stereoscope and various devices for measuring heights from images. The development of photogrammetry, a science that deals with measuring and mapping the earth's surface using aerial photographs, has made it possible to significantly speed up the compilation of maps and improve their accuracy. The use of aero and satellite images made it easier to update obsolete maps. Although aerial photographs good picture surfaces, they still cannot replace cards; they contain a lot of "unsorted" information, so they require interpretation. On the map, relatively less important data can be omitted, while other, more significant for the purposes of this map, on the contrary, are highlighted for easier reading. Moreover, both within the same image and on different images of the same series, there are various image distortions and violations of its scale. Therefore, in order to use images for compiling detailed maps, they must be brought to a single scale and corrected.

Some of the problems of mapping can be illustrated by the example of coastlines demarcating land and water areas. Since there are tides, the boundaries of the continents and oceans change in accordance with the change in the level of the World Ocean; usually maps show their position at mean sea level (i.e., the average between high and low tide levels). Moreover, even the largest scale maps cannot show all the details of the coastline; therefore, generalization is necessary.

The value of generalization, i.e. selection and generalization of details, increases as the scale of maps decreases; almost all elements of the basis and content of the map are subjected to generalization. For example, of the streams depicted on a large-scale topographic map, only a few can be preserved on a medium-scale map; when moving to overview maps, further selection and reduction in the number of elements is required. When selecting and generalizing, it is also necessary to establish the principles of selection - for example, when choosing criteria for displaying settlements, it is necessary to decide whether to be guided only by population or also take into account the political significance of cities; in the latter case, it is necessary to show all the capitals on the map, although their population may be low.

One of the most difficult tasks of mapping is the correct rendering of the terrain. In this case, methods such as hillshade, rendering of relief forms, isohypses, hatching and layered hypsometric coloring are used. Contours can be thought of as lines of intersection of a topographic surface by a series of equally spaced horizontal planes; the distance between these planes along the vertical is called the horizontal section. As a quantitative indicator, contour lines are very informative, but this method has some disadvantages - for example, small landforms may not be reflected on the map even with a small section, and, in addition, the relief in such an image is not very clear. In some cases, difficulties are overcome with the help of plastic hillshade - in addition to contour lines, shadows are applied to the relief image in accordance with the main skeletal lines, giving a qualitative characteristic, i.e. distribution of light and shadow for a given (oblique or vertical) illumination. A similar effect can be obtained when photographing an illuminated terrain model. Theoretically, even very small landforms can be shown with the help of shadow hillshading, if they are expressed at this scale at all. The combination of contour lines and hillshade achieves the most accurate, qualitatively and quantitatively, transfer of surface shapes.

The display of the relief by means of strokes differs in that the strokes are drawn along the dip of the slope (and not along the strike, like horizontal lines). The thickness of the strokes depends on the slope angle; the steeper the slope, the thicker the line, causing steeper slopes to appear darker on the map. Hatching can show sharp ridges and steep ledges; when drawing contours, even the most careful, these forms usually look smooth. The use of echo sounding makes it possible to perform detailed mapping of the topography of the ocean floor.

The oldest method of showing the outlines of the earth's surface is the use of perspective conventional signs, which are a stylized image of certain landforms in profile or in a 3/4 perspective. At the same time, their appearance, of course, differs from the planned image characteristic of the map, and, accordingly, some of them turn out to be displaced with respect to the true coordinates. Such a shift is tolerable on overview maps, but unacceptable for maps of large scales. Therefore, schematic signs depicting landforms are usually used only on small-scale maps. Previously, only the largest objects were transmitted in this way; small forms are also shown on modern physiographic maps. In this case, it is necessary to exaggerate the vertical scale compared to the horizontal one, since otherwise the relief forms look too flat and inexpressive.

The image of the relief on hypsometric maps is the highest degree of generalization of the contour lines method. Like the depiction of landforms with stylized perspective signs, this method is mainly used on overview maps. On hypsometric maps, each altitudinal zone is painted over with a certain color (or shade). A line can be drawn along the contact of two high-rise steps highlighted in different colors. At the same time, in each individual altitudinal belt, which sometimes spans hundreds of meters vertically, many details of the relief structure are not reflected on the map.

Traditionally, hypsometric maps used a specific color scale, in which shades of green, yellow and brown succeeded each other in ascending order of height; now some cartographers are refusing to do so. However, there is a tradition of depicting a number of mapped objects in a certain color. For example, brown is used for contour lines, blue for water features, red for settlements, and green for vegetation. The use of color not only makes the map more attractive, but also allows additional information to be presented.

statistical maps.

Small-scale statistical maps deserve special mention because of their increasing importance. These maps are usually based on quantitative sources such as census data. Among the methods of transmitting information, point methods, isopleth, choropleth (cartogram) and cartogram methods should be indicated. All of these methods can be used for the same data. Dot icons of the same size, each representing the same number of units of the depicted phenomenon , are plotted on the map according to the actual location of the phenomenon; the accumulation or sparseness of points shows the distribution (density) of the mapped phenomenon. Isopleths are isolines connecting points with the same values ​​of some relative indicator calculated on the basis of other indicators (and not measured directly). An example is the isolines of average monthly temperatures (calculated index). In the Horoplet system, a specific territorial statistical unit (for example, an administrative district) is considered as homogeneous in terms of a given statistical indicator; spatial differentiation is achieved by dividing the selected units into classes according to the size of the mapped feature and assigning a specific color to each class. On map diagrams, areas that are statistically homogeneous with respect to the selected attribute are shown regardless of the boundaries of territorial units, the data for which are the basis of the map.

Two more methods often used for statistical maps are signs, the size of which depends on the quantitative characteristic of the phenomenon depicted, and signs showing the direction of movement. In the first method, used in the case of precisely localized phenomena, such as the urban population, the dot signs have different weights; the size of signs is chosen in proportion to their weight and has several gradations (for example, according to the number of city residents). Movement signs may also include a quantitative characteristic (for example, the volume of shipping). This effect is achieved by changing the thickness of the lines.

HISTORY OF THE DEVELOPMENT OF CARTOGRAPHY

The universality of the cards is evidenced by the fact that even the so-called. primitive peoples make maps that perfectly suit their needs. For example, the Eskimos, without any measuring instruments at their disposal, made maps of vast areas of northern Canada, which do not lose much when compared with maps of the same territories compiled using modern methods. Similarly, the nautical charts compiled by the inhabitants of the Marshall Islands provide exceptionally interesting examples of "primitive" cartography. In these maps, the "grid" is formed by the midribs of the palm leaves, representing the open sea, and the arcuate lateral veins correspond to the front of the waves approaching the islands; the islands themselves are marked with clam shells. There has been a growing interest in Aboriginal maps, including American Indians.

In addition to rock paintings, the oldest maps compiled in Babylon and ancient Egypt have come down to us. Babylonian maps on clay tablets dated to about 2500 BC show features ranging in size from a single landholding to a large river valley. On the lid of one Egyptian sarcophagus is a stylized map of the roads of ancient Egypt. Chinese cartography also dates back to ancient times. In China, some very important techniques were developed a long time ago and independently of the West, including a rectangular cartographic grid used to determine the location of an object.

With regard to ancient Greece, although we have only a few examples of maps from this era, it is known from literary sources that the Greeks greatly surpassed other peoples in this area. Already in the 4th c. BC. the Greeks came to the conclusion about the sphericity of the Earth and divided it into climatic zones, from which the concept of latitude later arose. Eratosthenes in the 3rd c. BC. using simple geometric constructions, he amazingly accurately determined the dimensions of the Earth. He also owns a map of the world, on which lines of latitude and longitude were shown (although not in a modern ordered form). The representation of geographic coordinates in the form of a regular grid with equal intervals, attributed to the Greek astronomer Hipparchus, was used by the famous Greek cartographer Ptolemy, who lived in the 2nd century BC. AD in Alexandria. Ptolemy compiled a gazetteer that included ca. 8000 points with their coordinates, and developed a manual for the compilation of maps, from which, many centuries later, scientists were able to reconstruct some of the maps he compiled. After Ptolemy, cartography in the West fell into decline, although the Romans did a lot of land surveying. and compiling road maps.

Significant progress in cartography was made in China: compiled there in the 12th century. maps are superior to any other from this time. It is China that is credited with issuing the first printed map ca. 1150 ( see fig.). Meanwhile, the Arabs, using data from astronomical observations, learned to determine the latitude and longitude of any place much more accurately than Ptolemy could. Most of the maps drawn up in Europe in the Middle Ages were either extremely sketchy, such as road maps for pilgrims, or were overloaded with religious symbolism. The most common were cards like "T in O"; The earth was depicted on them in the form of a disk, and the letter "O" depicted the ocean surrounding the land; the vertical line of the letter "T" represented the Mediterranean Sea, and the rivers Nile and Don constituted, respectively, the right and left parts of the upper crossbar. These bodies of water separated Asia (located at the top of the map), Africa, and Europe on the map.

At the beginning of the 14th century a new type of map appeared in cartography. These were sea charts - portolans, which served navigational purposes; their creation became possible due to the appearance in Europe of a magnetic compass. Initially, these maps, embellished with a schematic representation of a compass and characterized by extremely detailed study of coastlines, were compiled only for the Mediterranean. In some respects, the pinnacle of medieval cartography is the small globe made by Martin Behaim in 1492, showing the world as it appeared before the discovery of America. This is the oldest globe.

Great geographical discoveries of Europeans in the second half of the 15th century. provided to the cartographers of the Renaissance new material. At the same time, scholars rediscovered and translated from ancient Greek the works of Ptolemy, the dissemination of which was made possible by printing. The development of printing has revolutionized cartography, making maps much more accessible. In particular, the production of maps has increased dramatically in the Netherlands. The central role in this process was played by Gerard Mercator (1512–1594), who specified the position of many points on the world map, developed map projections and created a major atlas, published after his death. The first atlas in the modern sense was a collection of maps published by the Flemish Abraham Ortelius under the title Spectacle of the globe (Theatrum orbis terrarum). The success of these ventures led to the flourishing of the card trade; in the centuries that followed, the industry declined due to a lack of new ideas.

A new impetus to the development of cartography was given in the 17th century. as a result of the activities of newly formed scientific societies, such as the Royal Society of London or the Royal Academy of Sciences in Paris. These organizations financed scientific expeditions, and also made a lot of efforts to more accurately determine the shape of the Earth and the location of individual points, which contributed to a significant progress in cartography. An important role in the development of topographic cartography was played by the invention of the theodolite, scale, barometer, and pendulum clocks, as well as by the development of new imaging methods (isolines, shading, etc.). Modern topographic survey on the scale of the whole country was begun in France in the 18th century.

In the 19th century there have been notable advances in small-scale mapping and especially in the development of quantitative cartography. At the end of the 19th century German geographer Albrecht Penk spoke at the International Geographical Congress with a proposal to create an International Map of the World. This project was carried out in the 20th century. In our century, the use of aerial photographs has become widespread. Ideas about the structure of the earth's surface and the shape of the Earth have been significantly enriched thanks to observations from artificial satellites, from which materials were obtained for mapping and other celestial bodies.

ORGANIZATIONS AND ENTERPRISES ENGAGED IN COMPILATION AND PUBLICATION OF MAP

Mapping the earth's surface has been and remains the lot of various international organizations. For example, the UN, in addition to financing the International Map of the World, allocates funds to mapping organizations. The international exchange of cartographic information is facilitated by the International Cartographic Association, which holds regular meetings and publishes a reference yearbook ( The International Yearbook of Cartography). Another international publication, the magazine Imago Mundi (translated as "The Image of the World"), is devoted to the history of cartography.

Topographic survey of the territories of individual countries is usually carried out by the forces of these countries. In many countries, national surveying and topographical work originally served military purposes; An example is the UK Film Service, responsible for the preparation of topographic maps of the territory of this country. In the US, there are more than a dozen federal organizations involved in topographic surveys in the country; the largest of these is the US Geological, Surveying and Mapping Service, whose main residence is in Washington. Surveying the US coastal zone and providing the necessary geodetic base for this are assigned to the US Coast and Geodetic Survey. Other US mapping organizations include the Department of Defense Surveying and Cartography Administration, which deals with topographic, hydrographic, and aerospace surveys. In many countries, national atlases are produced by various organizations, partly or wholly financed by the government.

In some countries, geographical societies occasionally issue thematic maps as supplements to their periodicals. The US Geographic Society, for example, features a variety of political and thematic maps in most issues of its popular magazine, National Geographic.

Commercial mapping companies often specialize in the production of a particular type of mapping product. Some issue road maps, others wall maps and atlases for schools, colleges and universities, others specialize in publishing cadastral maps for the needs of lawyers, tax inspectors, etc. The center for commercial map publishing in the United States is located in Chicago. In many countries, such enterprises are located in the capitals. Collecting cards, especially old ones, is widespread in the United States. For collectors, a special magazine "The Map Collector" is published. Many facsimile copies are commercially available. vintage maps and atlases.

In the United States, the most complete collection of maps and atlases, including both modern and ancient editions published in various countries, is located in the Cartographic Department of the Library of Congress in Washington. Copies of maps issued by US federal agencies, as well as handwritten maps produced by the same agencies, are held by the National Archives and Records Administration in Washington. The same functions in Great Britain and France are carried out, respectively, by the cartographic department of the British Library in London and the National Library in Paris. The Vatican Library in Rome has a large collection of old and very valuable maps.

Literature:

Salishchev K.A. Cartology. M., 1976
Berlyant A.M. Cartographic research method. M., 1978
Brief Topographic and Geodetic Dictionary. M., 1979
Salishchev K.A. Cartography. M., 1982
Berlyant A.M. Image of space: map and informatics. M., 1986