What do the signs on the map mean? Symbols of geographic maps

Symbols that we see on modern maps and plans did not appear immediately. On ancient maps, objects were depicted using drawings. Only starting from the middle of the 18th century, drawings began to be replaced by such images as objects look from above, or to designate objects with special signs.

Symbols and legend

Symbols- these are symbols denoting various objects on plans and maps. Ancient cartographers strove to convey the individual characteristics of objects with the help of signs. Cities were depicted in the form of walls and towers, forests - with drawings of different types of trees, and instead of the names of cities, small banners were applied with the image of the coats of arms or portraits of the rulers.

Currently, cartographers use a wide variety of conventional symbols. They depend on the degree of detail, the coverage of the territory and the content of the cartographic image. Signs for plans and large-scale maps make them look like the objects depicted. Houses, for example, are marked with rectangles, the forest is painted over in green. According to the plans, you can find out what material the bridge is made of, what types of trees it consists of, and get a lot of other information.

The values ​​are shown in the legend. Legend an image of all conventional zpacks that are used on a given plan or map, with an explanation of their meanings. The legend helps to read the plan and map, that is, to understand their content. With the help of conventional signs and legends, one can represent and describe terrain objects, find out their shape, size, some properties, and determine their geographical position.

According to their purpose and properties, the conventional signs of plans and maps are divided into three types: linear, areal and point.

Linear signs depict roads, pipelines, power lines, borders. These marks tend to exaggerate the width of an object, but accurately indicate its extent.

Areal (or scale) signs serve to represent objects, the dimensions of which can be expressed in a given map or plan. This is, for example, a lake, a piece of forest, a garden, a field. According to the plan or map, using a scale, you can determine their length, width, area. Areal signs, as a rule, consist of a contour and signs filling the contour or color coloring. All water bodies (fresh lakes, swamps, seas) on any plans and maps are blue. Green color on plans and large-scale maps denotes areas with vegetation (forests, shrubs, gardens).

Point (or off-scale) marks these are dots or special graphic icons. They display small objects (wells, water towers, detached trees on plans, settlements, deposits on maps). Due to their small size, such objects cannot be expressed in scale, therefore, their size cannot be determined from the cartographic image.

Many objects, which are indicated by icons on maps, are displayed on plans with areal conventional symbols. These are, for example, cities, volcanoes, mineral deposits.

The plans and maps contain many of their own geographical names, explanatory captions, and numbers. They provide additional quantitative (length and width of the bridge, depth of a reservoir, height of a hill) or qualitative (temperature, salinity of waters) characteristics of objects.

Topographic (cartographic) conventional signs - symbolic line and background symbols of terrain objects used to display them on topographic maps .

For topographic conventional signs, a common designation (in outline and color) of homogeneous groups of objects is provided, while the main signs for topographic maps different countries do not have any special differences among themselves. As a rule, topographic conventional signs convey the shape and size, location and some qualitative and quantitative characteristics of objects, contours and relief elements reproduced on maps.

Topographic conventional signs are usually divided into large-scale(or areal), off-scale, linear and explanatory.

Large-scale, or areal conventional signs are used to depict such topographic objects that occupy a significant area and whose dimensions in plan can be expressed in terms of scale of this card or plan. An area conventional sign consists of a sign of an object border and signs filling it or a conventional color. The contour of the object is shown with a dotted line (the contour of a forest, meadow, swamp), a solid line (the contour of a reservoir, a settlement) or a conventional sign of the corresponding border (ditches, hedges). Fill signs are located inside the outline in a certain order (arbitrarily, in a checkerboard pattern, in horizontal and vertical rows). Area symbols allow not only finding the location of an object, but also assessing its linear dimensions, area and outlines.

Out-of-scale symbols are used to convey objects that are not expressed at the scale of the map. These signs do not allow judging the size of the depicted local objects. The position of the object on the ground corresponds to a certain point of the sign. For example, for a sign of a regular shape (for example, a triangle denoting a point of a geodetic network, a circle - a cistern, a well) - the center of the figure; for a sign in the form of a perspective drawing of an object (a factory chimney, a monument) - the middle of the base of the figure; for a sign with a right angle at the bottom (wind turbine, gas station) - the top of this corner; for a sign combining several figures (radio mast, oil rig), the center of the lower one. It should be noted that the same local objects on maps or large-scale plans can be expressed by areal (large-scale) conventional symbols, and on small-scale maps - by out-of-scale conventional signs.

Linear conventional signs are intended for depicting extended objects on the ground, for example, iron and car roads, clearings, power lines, streams, borders and others. They occupy an intermediate position between large-scale and extra-scale conventional symbols. The length of such objects is expressed at the scale of the map, and the width on the map is out of scale. Usually it turns out to be larger than the width of the depicted terrain object, and its position corresponds to the longitudinal axis of the conventional sign. Linear topographic conventional symbols also represent horizontal lines.

Explanatory symbols are used to further characterize local items shown on the map. For example, the length, width and carrying capacity of a bridge, the width and nature of the road surface, the average thickness and height of trees in the forest, the depth and nature of the ford soil, etc. Various inscriptions and proper names of objects on maps are also explanatory; each of them is executed in the established font and letters of a certain size.

On topographic maps, as their scale diminishes, homogeneous conventional signs are combined into groups, the latter into one generalized sign, etc., in general, the system of these designations can be represented as a truncated pyramid, at the base of which are signs for topographic scale plans 1: 500, and at the top - for survey-topographic maps of scale 1: 1,000,000.

The colors of the topographic symbols are the same for maps of all scales. Dashed marks of lands and their outlines, buildings, structures, local objects, control points and boundaries are printed in black when published; relief elements - brown; reservoirs, streams, swamps and glaciers - in blue (water surface - in light blue); areas of tree and shrub vegetation - green (dwarf forests, elfin trees, shrubs, vineyards - light green); neighborhoods with fire-rated buildings and highways - orange; districts with non-fire-resistant buildings and improved dirt roads - yellow.

Along with conventional signs for topographic maps, conditional abbreviations of the proper names of political and administrative units (for example, Moscow region - Moscow) and explanatory terms (for example, power plant - el. ... Standardized fonts for inscriptions on topographic maps allow, in addition to conventional symbols, to provide essential information. For example, fonts for the names of settlements reflect their type, political and administrative significance and population, for rivers - the size and possibility of navigation; fonts for elevation marks, characteristics of passes and wells make it possible to highlight the main ones, etc.

The terrain relief on topographic plans and maps is depicted by the following methods: methods of strokes, hillshade, colored plastic, elevations and contour lines. On large-scale maps and plans, the relief is depicted, as a rule, by the method of contour lines, which has significant advantages over all other methods.

All conventional signs of maps and plans should be clear, expressive and easy to draw. Symbols for all scales of maps and plans are established by normative and instructive documents and are mandatory for all organizations and departments performing survey work.

Taking into account the variety of agricultural land and objects, which does not fit into the framework of mandatory conventional signs, land management organizations issue additional conventional signs reflecting the specifics of agricultural production.

Local objects are shown in varying detail depending on the scale of the maps or plan. So, for example, if not only individual houses, but also their shape will be shown on a 1: 2000 scale plan in a settlement, then on a 1: 50,000 scale map - only neighborhoods, and on a 1: 1 000 000 scale map the entire city will be indicated in a small circle. Such a generalization of the elements of the situation and relief during the transition from larger scales to smaller ones is called generalization of maps .

Definition 1

Cartographic Symbols- Symbolic graphic symbols that are used to represent various objects and their characteristics on cartographic images (maps and topoplans).

Sometimes the symbols are called the legend of the map.

Types of symbols by scale

Depending on the scale, $ 3 $ groups of conventional signs are distinguished:

• large-scale (areal and linear);
• off-scale (point);
• explanatory.

With the help of areal scale signs, extended objects are displayed on a map scale. On the map, scale signs allow you to determine not only the location of the object, but also its size and shape.

Example 1

Scale signs are the territory of the state on a map with a scale of $ 1: 10,000,000 $ or a reservoir on a map with a scale of $ 1: 10,000 $.

Linear symbols are used to display objects that are significantly extended in one dimension, for example, roads. Only one dimension is consistent with the scale on such signs (along which the object is the most extended), while the other is off-scale. The position of an object is determined by a conditional or explicit centerline.

Out-of-scale point marks are used in maps to display features that are not dimensioned on the map. The largest cities on the world map are displayed by off-scale signs - dots. The actual placement of the object is determined by the main point of the dot symbol.

The main point is placed at the off-scale marks as follows:

• in the center of the figure at symmetrical signs;
• in the middle of the base for characters with a wide base;
• at the top of the right angle, which is the base, if the sign has such an angle;
• in the center of the bottom shape if the character is a combination of several shapes.

Explanatory signs are intended to characterize local items and their varieties. Explanatory signs can indicate the number of railway tracks, the direction of the river flow.

Remark 1

On large-scale maps, signs of individual objects are indicated separately, on maps of a smaller scale - objects of the same type are grouped and applied with one sign.

Symbols by content

1. signs and signatures of settlements;
2. signs of individual local objects;
3. signs individual elements relief;
4. transport infrastructure signs;
5. signs of objects of the hydrographic network;
6. land cover signs;

Signs and signatures of settlements

On maps of a scale of $ 1: $ 100,000 and larger, all settlements are indicated along with the signature of their names. Moreover, the names of cities are applied in direct capital letters, rural settlements - in lowercase letters, urban and suburban settlements - in lowercase oblique letters.

On the large-scale maps external outlines and layouts are displayed, highlighting the largest highways, enterprises, outstanding knowledge and landmarks.

Example 2

On maps with a scale of $ 1: 25 \ 000 $ and $ 1: 50 \ 000 $, the type (refractory or non-refractory) building is displayed in color.

The figure below shows the signs of settlements used on maps of different eras.

Signs of selected local sites

Individual local objects, which are landmarks, are drawn on the map mainly with off-scale signs. These can be towers, mines, adits, churches, radio masts, outlier rocks.

Signs of individual relief elements

Relief elements are drawn on the map with appropriate signs.

Remark 2

Natural objects are depicted with brown lines and marks.

Transport infrastructure signs

The objects of transport infrastructure displayed on topographic maps include the road and railway network, structures and bridges.

When mapping, separate roads with and without paved roads (freeways, improved highways, improved dirt roads). All paved roads are plotted on the map, indicating the width and material of the pavement.

The color of the road on the map indicates its type. Highways and highways are drawn in orange, improved dirt roads are yellow (occasionally orange), unpaved country roads, field, forest and seasonal roads without color.

Hydrographic network objects signs

The map depicts the following elements of the hydrographic network - the coastal part of the seas, rivers, lakes, canals, streams, wells, ponds and other bodies of water.

Reservoirs are mapped if their area is more than $ 1 mm ^ 2 $ on the image. Otherwise, the body of water is deposited only because of its high significance, for example in arid regions. The names of the objects are indicated next to them.

The characteristics of the objects of the hydrographic network are indicated next to the signature of the name of the object. In particular, indicate in the form of a fraction the width (numerator), depth and nature of the soil (denominator), as well as the speed (in m / s) and the direction of the current. Also indicated along with the characteristics of hydraulic structures - ferries, dams, locks. Rivers and canals are fully mapped. In this case, the type of display is determined by the width of the object and the scale of the map.

Remark 4

In particular, at a map scale of more than $ 1: $ 50,000, objects with a width of less than $ 5 $ m, at a scale of less than $ 1: $ 100,000 - less than $ 10 $ m, depict $ 1 $ as a line, and wider objects - in two lines. Also, $ 2 $ lines indicate channels and ditches with a width of $ 3 $ m and more, and with a smaller width - one line.

On large-scale maps, blue circles represent wells, next to it is the letter "k" or "art.k" in the case of an artesian well. In arid regions, wells and water supplies are shown with enlarged signs. Water pipelines on maps are shown with lines with dots in blue: solid lines - above ground, broken lines - underground.

Land cover signs

Often, when displaying land cover on a map, a combination of large-scale and off-scale conventional symbols is used. Signs denoting forests, shrubs, gardens, swamps, meadows, nature are large-scale, and individual objects, for example, freestanding trees, are off-scale.

Example 3

A swampy meadow is displayed on the map as a combination of conventional symbols of meadows, bushes and swamps in a closed contour.

The contours of terrain areas occupied by forest, shrubs or swamps are drawn with a dotted line, unless the boundary is a fence, roads or other linear local object.

Forested areas are indicated in green with a symbol indicating the type of forest (coniferous, deciduous or mixed). Areas with undergrowth or nurseries are plotted in pale green.

Example 4

The picture below, on the left, shows a coniferous pine forest with an average tree height of $ 25 $ meters and a width of $ 0.3 $ m, as well as a typical spacing between tree trunks $ 6 $ m. The picture on the right is a deciduous maple forest with $ 12 $ m trees. and a trunk width of $ 0.2 $ m, the distance between which is on average $ 3 $ meters.

Swamps are shown on the map with blue horizontal shading. In this case, the type of hatching shows the degree of passability: intermittent hatching - passable, solid - difficult and impassable.

Remark 5

Swamps with a depth of less than $ 0.6 $ m are considered passable.

Vertical blue shading on the map indicates salt marshes. As for swamps, solid shading indicates impassable salt marshes, and intermittent shading indicates passable ones.

Symbols on topographic maps

The colors used for depicting objects on maps are universal for all scales. Black line marks - buildings, structures, local objects, strong points and borders, brown line marks - relief elements, blue - hydrographic network. Areal signs in light blue are the water mirror of the objects of the hydrographic network, green - areas of trees and shrubs, orange - quarters with fire-resistant buildings and highways, yellow - quarters with non-fire-resistant structures and improved dirt roads.

Remark 6

On military and special maps, special symbols are applied.

I got acquainted with military topography in the second year of my institute. The symbols used there differ slightly from the general topographic ones due to the need to designate completely different objects. Moreover, the color palette is widely used there, which, in my opinion, makes these maps more readable.

Conventional tactical signs

Such signs on military maps designate their troops and enemy troops, the types of units (infantry, tanks) in the operational theater, the placement of defensive structures, the direction of probable strikes, etc. cards cannot be. For example, military helicopters alone can have several different image options, depending on their purpose: reconnaissance, combat, anti-submarine, etc. Colors play an important role for the dynamic information of the map. In the Russian army, it is customary to use the following colors:

• Red is our troops. The same color is used to denote fires.
• Blue - enemy troops. It is also for flooded areas.
• Black is the position when moving our troops.
• Brown - roads and routes.
• Green - the boundaries of radioactive contamination.

The army of each military bloc has its own colors and designations.

Symbols for subdivisions

As the teacher explained to me, the military map should be as difficult as possible for the enemy to read. Therefore, the images used on it should not be read intuitively. Roughly speaking, the tank should not be marked as a square with a line.

However, general requirements for their commanders must exist. At the time when plans were drawn by hand, an officer's line was suitable for these purposes. Yes, it is still used today when creating large-scale plans, when it is necessary to accurately and quickly, in relatively calm conditions, sketch out a plan. But still, in all countries of the world, not even on purpose, but there are objects that are designated the same way. For example, a radio station both in the Russian Federation and in the NATO countries is symbolized by a lightning icon.

Comparison of the properties of a geographical map and a plan of the area.

Area plan. Geographic map

Map- a reduced generalized symbolic image of the Earth's surface (its part), other planets or the celestial sphere, built in scale and projection.

Site plan- a drawing of the area, made in conventional signs and on a large scale (1: 5000 and larger).

When building plans, the curvature of the earth's surface is not taken into account, because small territories or areas of terrain are depicted.

The difference between a terrain plan and a geographic map:

1) the plans show small areas of the terrain, so they are built on a large scale (for example, 1 cm - 5 m). Geographic maps show much larger territories, their scale is smaller;

2) the plan depicts the terrain in detail, preserving the exact outlines of the depicted objects, but only in a reduced form. The large scale of the plan allows you to reflect on it almost all objects located on the ground. All objects cannot be plotted on a map with a smaller scale, therefore, when creating maps, objects are generalized. The exact outlines of all objects on the map also cannot be shown, therefore they are distorted to one degree or another. Many objects on the map, in contrast to the plan, are depicted by off-scale conventional symbols;

3) when building a plan, the curvature of the earth's surface is not taken into account, since a small area of ​​the terrain is depicted. When building a map, it is always taken into account. Maps are built in certain cartographic projections;

4) there is no degree network on the plans. Parallels and meridians are necessarily put on the map;

5) on the plan, the north-south direction is by default considered the upward direction, the southward direction is downward, the westward — leftward, eastward — rightward direction (sometimes the north-south direction on the map is shown by an arrow that does not coincide with the upward and downward direction). On maps, the north-south direction is determined by the meridians, the west-east direction is determined by the parallels.

Comparison of methods of cartographic representation. Methods for displaying objects and phenomena on geographical maps

Symbols- designations used on maps to depict various objects and their qualitative and quantitative characteristics. Symbols are used to designate both real objects (for example, settlements) and abstract (for example, population density). Symbols are intended to indicate the type and some characteristics of objects (phenomena) depicted on the map and to determine their position in space.

Symbols are:

— off-scale(used to depict objects that cannot be expressed at the scale of the map). These are drawings or geometric shapes, the shape of which usually resembles the depicted object (Fig. 1). Alphabetic symbols also refer to off-scale symbols. The position of the object on the ground corresponds to the center of the sign with a symmetrical shape, the middle of the base of the sign with a wide base, the top of the corner of the sign with the base in the form of a right angle, the center of the lower figure of the sign, which is a combination of several figures;

— linear(used to represent objects of a linear nature - rivers, roads, borders, pipelines, etc.). In scale, they convey only the length and shape of the object, their width is exaggerated, so it cannot be measured (Fig. 2);

— areal, or outline(used to represent geographic objects that occupy a certain area - a lake, a forest, etc.). They transmit the actual size of the objects (Fig. 3).

They consist of a contour (forest, swamp, etc.) and its filling (color, shading).

Explanatory conventional signs (for example, arrows showing the direction of the river flow, figurines of deciduous and coniferous trees, etc.), signatures, alphabetic and numerical designations also carry certain information on the map.

Cartographic methods of representation

A quality background method. It is used for the image on the map of the qualitative features of certain objects or phenomena that have a continuous distribution on the earth's surface or occupy large areas. Its essence lies in the fact that on the map, areas that are homogeneous according to a certain attribute (attributes) (for example, natural zones) are distinguished and painted over (or hatched) in colors (shading) selected for them.

Areal method. Area- the area of ​​distribution on the earth's surface of any phenomenon (for example, the territory in which a certain animal lives, or the territory in which this or that agricultural crop is grown, etc.).

Isolines method. Isolines(from the Greek isos - equal) - lines on geographic maps ah, passing through points with the same value of any quantitative indicator (temperature, precipitation, depth, height, etc.) characterizing the depicted phenomenon. For example, isotherms are lines connecting places with the same temperature; isobaths - lines connecting places with the same depth; horizontals - lines connecting points on the earth's surface with the same absolute height. The essence of the isoline method is that on the map points with the same values ​​of a certain indicator are connected by thin lines, that is, isolines are drawn.

Lines of movement. Lines (arrows) show the direction of movement of any objects - air masses, winds, ocean currents, rivers, etc.

Determination of directions, measuring distances on the plan and map

On the plan north - south is shown by an arrow. If there is no arrow on the plan, then it is considered that north is at the top, south is at the bottom.

On the map, directions are determined using a degree network. The north - south direction corresponds to the direction of the meridians, west - east - the parallels.

Azimuth measurements the maps are produced using a protractor. Azimuth- the angle formed at a given point or on the map between the direction to the north and any object and counted clockwise.

So, if the object is located strictly north of the point at which the observer is, then the azimuth to it will be 0 °, to the east - 90 °, to the south - 180 °, to the west - 270 °. Azimuths can range from 0 ° to 360 °. In order to measure the azimuth on the map, you need to draw a line parallel to the north-south direction through the starting point of the direction to be determined. Then, also through the point, draw a line connecting the point and the object to which you want to determine the azimuth. And then, using a protractor, measure the resulting angle (azimuth), taking into account that the azimuth is always counted clockwise.

Determination of geographic coordinates

Degree network and its elements. Degree network of the Earth- a system of meridians and parallels on geographic maps and globes, which serves to count the geographic coordinates of points on the earth's surface - longitudes and latitudes - or to map objects by their coordinates.

Certain reference points are required to create a degree network. The spherical shape of the Earth determines the existence on the earth's surface of two fixed points - the poles. An imaginary axis passes through the poles, around which the Earth rotates.

Geographic poles- mathematically calculated points of intersection of the imaginary axis of rotation of the Earth with the earth's surface.

Equator- an imaginary line on the earth's surface, obtained by mentally cutting an ellipsoid into two equal parts (Northern and Southern hemispheres). All points on the equator are equidistant from the poles. The equatorial plane is perpendicular to the Earth's axis of rotation and passes through its center. The hemispheres are mentally separated by many more planes parallel to the plane of the equator. The lines of their intersection with the surface of the ellipsoid are called parallels... All of them, like the equatorial plane, are perpendicular to the planet's axis of rotation. You can draw as many parallels as you like on the map and the globe, but usually they are drawn on training maps with an interval of 10-20 °. Parallels are always oriented from west to east. The circumference of parallels decreases from the equator to the poles. It is the largest at the equator and zero at the poles.

When imaginary planes cross the earth's axis, passing through the earth's axis perpendicular to the equatorial plane, large circles are formed - meridians... Meridians can also be drawn through any point of the ellipsoid. They all intersect at the points of the poles (Fig. 4). The meridians are oriented from north to south. Average arc length of 1 ° meridian: 40,008.5 km: 360 ° = 111 km. The length of all meridians is the same. The direction of the local meridian at any point can be determined at noon by the shadow of any object. In the Northern Hemisphere, the end of the shadow always shows the direction to the north, in the Southern Hemisphere - to the south.

The degree network is necessary to read the geographic coordinates of points on the earth's surface - latitude and longitude.

Geographic latitude- the distance along the meridian in degrees from the equator to any point on the Earth's surface. The starting point is the equator. The latitude of all points on it is 0. At the poles, the latitude is 90 °. North of the equator, north latitude is measured, south - south.

Geographic longitude- the distance along the parallel in degrees from the prime meridian to any point on the earth's surface. All meridians are equal in length, so one had to choose one of them for counting. It was the Greenwich meridian, which runs near London (where the Greenwich Observatory is located). Longitude is counted from 0 ° to 180 °. To the east of the prime meridian to 180 ° east longitude is counted, to the west - west.

Thus, using the degree network, you can accurately determine the geographical coordinates - the values ​​that determine the position of a point on the earth's surface relative to the equator and the prime meridian. For example, the geographical coordinates of Cape Chelyuskin (the northernmost point of Eurasia) are 78 ° N. sh. and 104 ° E etc.

Determining distances on the map

The scale is called the ratio of the length of a line in a drawing, plan or map to the length of the corresponding line in reality. The scale shows how many times the distance on the map is reduced relative to the real distance on the ground. If, for example, the scale of a geographical map is 1: 1,000,000, this means that 1 cm on the map corresponds to 1,000,000 cm on the ground, or 10 km.

Distinguish between numerical, linear and named scales.

Numerical scale It is depicted as a fraction, in which the numerator is equal to one, and the denominator is a number that shows how many times the lines on the map (plan) are reduced relative to the lines on the ground. For example, a scale of 1: 100,000 shows that all linear dimensions on the map are reduced by a factor of 100,000. Obviously, the larger the denominator of the scale, the smaller the scale, with a smaller denominator the larger the scale. The numerical scale is a fraction, so the numerator and denominator are given in the same measurements (centimeters).

Linear scale is a straight line divided into equal segments. These segments correspond to a certain distance on the depicted area; divisions are indicated by numbers. The measure of length along which the divisions are plotted on the scale bar is called the base of the scale. In our country, the scale base is taken to be 1 cm. The number of meters or kilometers corresponding to the scale base is called the scale value. When building a linear scale, the number 0, from which the divisions are counted, is usually placed not at the very end of the scale line, but stepping back one division (base) to the right; on the first segment to the left of 0, the smallest divisions of a linear scale are applied - millimeters. The distance on the ground corresponding to one smallest division of the linear scale corresponds to the scale accuracy, and 0.1 mm corresponds to the extreme scale accuracy. The linear scale in comparison with the numerical one has the advantage that it makes it possible to determine the actual distance on the plan and map without additional calculations.

Named scale- scale expressed in words, for example, 1 cm 250 km. (fig. 5):

Measuring distances on the map and plan. Measuring distances using a scale. To measure the distance, you need to draw a straight line (if you need to know the distance in a straight line) between two points and use a ruler to measure this distance in centimeters, and then multiply the resulting number by the magnitude of the scale. For example, on a map with a scale of 1: 100,000 (in 1 cm to 1 km), the distance is 5 cm, that is, on the ground, this distance is 1.5 = 5 (km). If you need to measure the distance between objects indicated by off-scale conventional symbols, then measure the distance between the centers of the conventional symbols.

Measuring distances using a degree network. To calculate distances on a map or globe, you can use the following values: the length of an arc of 1 ° meridian and 1 ° of the equator is approximately 111 km. The total length of the earth's meridian is 40,009 km. Due to the fact that the Earth is flattened at the poles (polar compression), the 1 ° arc length along the meridian at the equator (110.6 km) is less than at the poles (111.7 km). It is believed that the average length of the 1 ° meridian is 111.1 km. An arc length of 1 ° in parallels decreases towards the poles. At the equator, it can also be taken equal to 111 km, and at the poles - 0 (since the pole is a point). To determine the distance in kilometers between two points lying on the same meridian, the distance between them in degrees is calculated, and then the number of degrees is multiplied by 111.1 km. To determine the distance between two points on the equator, you also need to determine the distance between them in degrees, and then multiply by 111.1 km. To determine the distance between two points located on the same parallel, it is necessary to know the number of kilometers corresponding to the length of 1 ° of the arc of each particular parallel.

Determination of standard and zone time

Time Zones. Local and standard time. Solar time at points located on the same meridian is called local ... Due to the fact that at every moment of the day it is different on all meridians, it is inconvenient to use them. Therefore, according to international agreement, standard time has been introduced. The entire surface of the Earth was divided along the meridians into 24 belts of 15 ° longitude. Waist (the same within each belt) time - this is the local time of the median meridian of the given belt. Zero Belt - this is a belt, the median meridian of which is the Greenwich (zero) meridian. From it the belts are counted to the east.

Since 2014, 11 time zones have been established on the territory of Russia. The starting point for calculating the local time of the time zones is Moscow time - the time of the II time zone (see the map). Thus, the difference in time between the first time zone and the eleventh is 10 hours.

Conventionally, it is believed that a new day begins in the 12th time zone (through which the 180 ° meridian passes - the date change line). To the west of the date line, a new day begins (according to the calendar). Therefore, in the logbook of a ship sailing from west to east, one day must be counted twice, and a ship moving from east to west, as it were, "misses" one day, after December 31, immediately falls on January 2.

Use of statistical materials to determine trends in the development of geographic processes and phenomena

To reflect the trends in the development of processes, statistical tables are often used, where data is presented as a percentage of the previous year - the volume of production last year is 100%. Therefore, if any number greater than 100 is indicated in the table for the next year, then the volume of products produced this year was greater than in the previous one.

Building a relief profile on a map

Relief image on maps. Relief on maps is represented by contour lines, special symbols and elevation marks.

Horizontal lines- lines on the map along which all points on the earth's surface have the same absolute height. The difference between two heights of adjacent contours is called a relief section. The smaller the cross-section of the relief, the more detailed it is. The size of the relief section depends on the scale of the map and on the nature of the relief itself. The relief is shown in most detail on topographic maps. For example, on a map with a scale of 1: 25,000 (in 1 cm 250 m), solid contours are drawn every 5 m, and on a map of a scale of 1: 100,000 (in 1 cm 1 km), a relief section of 20 m is used for flat territories and 40 m for mountain. On small-scale maps, an uneven cross-section of the relief is usually used: more frequent in flat areas and enlarged in mountainous areas. So, on physical map In Russia, on a scale of 1: 25,000,000, horizontal lines are drawn at an altitude of 0, 200, 500, 1000, 2000, 3000, 4000 m. Isobaths (contours of depths) are also shown.

Horizontal lines can easily determine the absolute height of any point on the earth's surface and the relative height of two points (the excess of one above the other). Contour lines also help determine the steepness of slopes. The closer the horizontal lines are to one another, the steeper the slope. Additional information about the relief on topographic maps is given by bergstrichs- small strokes drawn perpendicular to the contours, indicating in which direction the relief is going down.

To depict landforms that are not expressed by horizontals (for example, sharp ledges, cliffs, ravines, etc.), special conventional symbols are used.

Absolute heights peaks or depressions on maps are signed with numbers. Absolute heights are indicated in meters.

Hydrographic elements help to understand the general nature of the relief change - for example, if a river is depicted on a map, then, as a rule, there is a general decrease in the relief of the right left bank to its channel. The direction of the river flow also shows the direction of the decrease in the absolute height of the points.