Height of various landforms. terrain

Despite the wide variety of unevenness of the earth's surface, the main forms of relief can be distinguished: a mountain, a basin, a ridge, a hollow, a saddle.

The top of the mountain, the bottom of the basin, the point of the saddle are characteristic points of the relief; the line of the watershed of the ridge, the line of the spillway of the hollow, the line of the foot of the mountain or the ridge, the line of the crest of the hollow or hollow are the characteristic lines of the relief.

Classification

Landforms vary:

Planetary landforms

Geosynclinal belts
mid-ocean ridges

Mega landforms

Relief macroforms

Separate ridges and depressions of any mountainous country Examples: Main Caucasian ridge, Bzyb ridge (Abkhazia) ...

Mesoforms of relief

relief microforms

Nanoforms of relief

Examples: meadow tussock, marmot, fine erosion grooves, ripple marks on the surface of eolian forms or on the seabed.

Relief imaging methods

The method of depicting the relief should provide a good spatial representation of the terrain, reliable determination of the directions and steepness of slopes and marks of individual points, and the solution of various engineering problems.

During the existence of geodesy, several methods have been developed for depicting relief on topographic maps. We list some of them:

promising way.
Washing method. This method is used on small scale maps. The surface of the Earth is shown in brown: the larger the mark, the thicker the color. The depths of the sea are shown in blue or green: the deeper the depth, the thicker the color.
Shading method.
Marking method. With this method, the marks of individual points of the terrain are signed on the map.
Horizontal method.

At present, topographic maps use the method of contour lines in combination with the method of marks, and, as a rule, at least five marks of points are signed on one square decimeter of the map.

Notes

Wikimedia Foundation. 2010 .

See what "Relief Form" is in other dictionaries:

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Hel spit (left), Baltic spit (center) and Curonian spit (right) on the coast of the Baltic Sea This term has other meanings, see Spit. A spit is a low alluvial strip of land on the coast of a sea or lake, with ... Wikipedia

A spit is a low alluvial strip of land on the shore of a sea or lake, connected at one end to the shore. Contents 1 Over the seas 1.1 Sea of Azov 1.2 ... Wikipedia

s; well. [lat. fōrma appearance, shape, appearance] 1. External outlines, external appearance of an object. The earth is spherical. square f. Curved object. Clouds change their forms. Vessels of various shapes. Water poured into a vessel takes the shape of a vessel. encyclopedic Dictionary

the form- s; well. (lat. fōrma appearance, appearance, appearance) see also. for the form, throughout the form, in the form, mold, formal, uniform ... Dictionary of many expressions

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Lesson questions:

1. Types and forms of terrain. The essence of the image of the relief on the maps by contour lines. Types of horizontals. Image by contour lines of typical landforms.

1.1 Types and forms of terrain.
In military affairs terrain understand the area of the earth's surface on which to conduct hostilities. The unevenness of the earth's surface is called terrain, and all objects located on it, created by nature or human labor (rivers, settlements, roads, etc.) - local items.
The relief and local objects are the main topographical elements of the terrain that affect the organization and conduct of combat, the use of military equipment in combat, the conditions for observation, firing, orientation, camouflage and maneuverability, i.e., determining its tactical properties.
A topographic map is an accurate representation of all the most tactically important elements of the terrain, plotted in a mutually exact arrangement relative to each other. It makes it possible to explore any territory in a relatively short time. Preliminary study of the terrain and decision-making for the performance of a particular combat mission by a subunit (unit, formation) is usually carried out on a map, and then refined on the ground.
The terrain, influencing combat operations, in one case can contribute to the success of the troops, and in the other have a negative effect. Combat practice convincingly shows that one and the same terrain can give more advantages to those who study it better and use it more skillfully.
According to the nature of the relief, the area is divided into flat, hilly and mountainous.
flat terrain characterized by small (up to 25 m) relative elevations and a relatively small (up to 2 °) steepness of slopes. Absolute heights are usually small (up to 300 m) (Fig. 1).

The tactical properties of flat terrain depend mainly on the soil and vegetation cover and on the degree of ruggedness. Clayey, loamy, sandy loamy, peaty soils allow the unhindered movement of military equipment in dry weather and significantly impede movement during the rainy season, spring and autumn thaws. It can be indented by riverbeds, ravines and gullies, have many lakes and swamps, which significantly limit the ability to maneuver troops and reduce the rate of advance (Fig. 2).
Flat terrain is usually more favorable for the organization and conduct of an offensive and less favorable for defense.

hilly area characterized by a wavy nature of the earth's surface, forming irregularities (hills) with absolute heights up to 500 m, relative elevations of 25 - 200 m and a prevailing steepness of 2-3 ° (Fig. 3, 4). The hills are usually composed of hard rocks, their tops and slopes are covered with a thick layer of loose rocks. The depressions between the hills are wide, flat or closed basins.

Hilly terrain provides for the movement and deployment of troops hidden from enemy ground observation, makes it easier to choose places for firing positions of missile troops and artillery, and provides good conditions for concentrating troops and military equipment. In general, it is favorable both for the offensive and for defense.
Mountain landscape represents areas of the earth's surface that are significantly elevated above the surrounding area (having absolute heights of 500 m or more) (Fig. 5). It is distinguished by a complex and varied relief, specific natural conditions. The main landforms are mountains and mountain ranges with steep slopes, often turning into rocks and rocky cliffs, as well as hollows and gorges located between mountain ranges. The mountainous area is characterized by a sharp rugged terrain, the presence of hard-to-reach areas, a sparse network of roads, a limited number of settlements, a rapid flow of rivers with sharp fluctuations in water levels, a variety of climatic conditions, and a predominance of rocky soils.
Combat operations in mountainous areas are considered as operations in special conditions. Troops often have to use mountain passes; observation and firing, orientation and target designation are difficult, at the same time it contributes to the secrecy of the location and movement of troops, facilitates the setting up of ambushes and engineering barriers, and the organization of camouflage.

1.2 The essence of the image of the relief on maps by contour lines.
The relief is the most important element of the terrain, which determines its tactical properties.
The image of the relief on topographic maps gives a complete and sufficiently detailed idea of the irregularities of the earth's surface, the shape and relative position, elevations and absolute heights of terrain points, the prevailing steepness and length of slopes.

1.3 Types of contour lines.
Horizontal- a closed curved line on the map, which corresponds to a contour on the ground, all points of which are located at the same height above sea level.
There are the following horizontal lines:

main(solid) - relief section corresponding to the height;
thickened - every fifth main horizontal; stands out for ease of reading the relief;
additional horizontals(semi-horizontals) - are drawn by a broken line at the height of the relief section equal to half of the main one;
auxiliary - are depicted as short dashed thin lines, at an arbitrary height.

Distance between two adjacent main contour lines in height are called the height of the relief section. The height of the relief section is signed on each sheet of the map under its scale. For example: "Solid contours are drawn through 10 meters."
To facilitate the calculation of contour lines when determining the heights of points on the map, all solid contour lines corresponding to the fifth multiple of the height of the section are drawn thickened and a number indicating the height above sea level is put on it.
In order to quickly determine the nature of surface irregularities on maps when reading a map, special slope direction indicators are used - berghashes- in the form of short dashes placed on the horizontals (perpendicular to them) in the direction of the slopes. They are placed on the bends of contour lines in the most characteristic places, mainly at the tops of saddles or at the bottom of basins.
Additional contours(semi-horizontals) are used to display the characteristic forms and details of the relief (bends of slopes, peaks, saddles, etc.), if they are not expressed by the main horizontals. In addition, they are used to depict flat areas, when the laying between the main contours is very large (more than 3 - 4 cm on the map).
Auxiliary horizontals used to depict individual details of the relief (saucers in the steppe regions, depressions, individual hillocks on flat terrain), which are not transmitted by the main or additional horizontals.

1.4 Depiction by contour lines of typical landforms.
The relief on topographic maps is depicted by curved closed lines connecting points of the terrain that have the same height above the level surface, taken as the origin of the heights. Such lines are called horizontal lines. The image of the relief with contour lines is supplemented by labels of absolute heights, characteristic points of the terrain, some contour lines, as well as numerical characteristics of relief details - height, depth or width (Fig. 7).

Some typical forms of terrain on the maps are displayed not only by the main, but also by additional and auxiliary contour lines (Fig. 8).


Rice. 8. Image of typical landforms

2. Determination on the map of absolute heights and relative elevations of terrain points, ascents and descents, steepness of slopes.

2.1. Determination on the map of absolute heights and relative elevations of terrain points

2.2. Definition on the map of ascents and descents on the route.

Rice. ten. Definition on the map of ascents and descents on the route of movement (route profile).

Rice. eleven. Determination on the map of the steepness of the slopes

Profile- a drawing depicting a section of the terrain with a vertical plane.
For greater expressiveness of the terrain, the vertical scale of the profile is taken 10 or more times larger than the horizontal one.
In this regard, the profile, transmitting the mutual excess of points, distorts (increases) the steepness of the slopes.
To build a profile, you need(Fig. 10) :

draw a profile line (travel route) on the map, attach a sheet of graphed (millimetric) paper to it, transfer to its edge with short lines the places of contour lines, the inflection points of the slopes and local objects that the profile line cuts, and sign their heights;
sign on a sheet of graphed paper at the horizontal lines the heights corresponding to the heights of the contour lines on the map, conventionally taking the gaps between these lines as the height of the section (set the vertical scale);
from all dashes indicating the intersections of the profile line with elevation marks of contour lines, inflection points of slopes and local objects, lower the perpendiculars until they intersect with parallel lines corresponding to the marks and mark the resulting intersection points;
connect the intersection points of a smooth curve, which will depict the terrain profile (ascents and descents on the route of movement).

2.3. Determination on the map of the steepness of the slopes.
The steepness of the slope on the map is determined by the location - the distance between two adjacent main or thickened horizontals; the smaller the laying, the steeper the slope \.
To determine the steepness of the slope, it is necessary to measure the distance between the horizontals with a compass, find the corresponding segment on the laying chart and read the number of degrees (Fig. 11).
On steep slopes, this distance is measured between thickened contours and the steepness of the slope is determined from the graph on the right.

3. Conventional signs of relief elements that are not expressed by contour lines.

	Ice cliffs (barriers) and outcrops of fossil ice (8 - height of the cliff in meters)

	Sod ledges (edges) that are not expressed by horizontal lines
	Shafts coastal, historical, etc., not expressed by contour lines (3 - height in meters)
	1) Dry channels in one line (less than 5 m wide); 2) Dry channels in two lines with a width of 5 to 15 m (0.5 mm on the map scale); 3) Dry channels more than 15 m wide (from 0.5 to 1.5 mm on a map scale); 4) Dry channels with a width of more than 1.5 mm on a map scale and basins of dry lakes
	Height marks
	Command Height Marks
	Landmark elevations
	Main passes, marks of their heights and duration
	Passes, marks of their heights and duration
	Karst and thermokarst sinkholes not expressed on the map scale
	Pits that are not expressed on the scale of the map
	Pits expressed in map scale
	Rocks-outliers that have a landmark value (10-height in meters)
	Rocks-outliers that do not have a landmark value
	Dikes and other narrow, steeply walled hard rock ridges (5 - height of the ridge in meters)
	Mud volcano craters
	Volcanic craters not expressed on the map scale
	Mounds and mounds that are not expressed on the scale of the map
	Mounds and mounds, expressed on the scale of the map (5 - height in meters)
	Clusters of stones
	Separately lying stones (3 - height in meters)
	Entrances to caves and grottoes

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Fundamentals of external and internal ballistics. Hand grenades. Grenade launchers and rocket-propelled grenades.

9.1. TYPES AND ELEMENTARY FORMS OF RELIEF

Relief - a set of uneven land, the bottom of the oceans and seas, diverse in shape, size, origin, age and history of development. It is composed of positive (convex) and negative (concave) shapes. Main forms relief are: mountain, hollow, ridge, hollow and saddle.
In addition to the above forms, the relief has details . Relief details include: ravines, gullies, mounds, embankments, cuts, ledges, quarries, etc.
All varieties of forms and relief details consist of elements. Main relief elements are: base (bottom), slope (slope), top (bottom), height (depth), steepness and direction of the slope, watershed and catchment lines (thalweg). The main forms, details and relief elements are shown in fig. 9.1.

Rice. 9.1. Basic forms, details and relief elements

mountain called a domed or cone-shaped elevation of the earth's surface. The highest point of the mountain is called summit, from which the terrain drops in all directions. The pointed top of the mountain is called peak, and flat plateau. The side of a mountain is called slope or slope. The base of the mountain, which is the line of transition of the slopes into the surrounding flat surface, is called sole the mountains. A small mountain, up to 200 m high, is called hill. The mound is called barrow.
Basin is a closed cone-shaped recess of the earth's surface. The lower part of the basin is called the bottom, the side surface is called the slope, the line of transition of the side surface to the surrounding area is eyebrow. The small basin is called pit, funnel or depression.
Ridge - it is a hill elongated in one direction with two opposite slopes. The line of intersection of its slopes, passing along the highest points of the ridge, is called watershed, from which water and precipitation slide down two slopes.
dell - an elongated recess. The line along the hollow, passing through the lowest points, is called watercourse or thalweg, and the sides stingrays, which end eyebrows. If you look down the watercourse, then the excesses in this direction will be negative, and to the right, left and back - positive. Wide hollows with gentle slopes are called valleys, and with steep and stony - gorges. Hollows in the form of deep gullies in valleys, formed under the action of flowing waters, are called ravines. Over time, the cliffs of the ravine crumble, overgrow with grass, woody vegetation and form beams.
saddle - this is a lower section of the watershed between two hills and two hollows, diverging from the saddle in opposite directions. In mountainous areas, a saddle is called a pass.
To depict the terrain at characteristic points of saddles, on the tops of mountains, at the bottom of basins, on the watersheds of ridges, watercourses of hollows, on the edges of hollows and hollows, on the soles of mountains and at the points of inflections of slopes during topographic survey, their heights are determined, which are then signed on the map around these points.

9.2. ESSENCE OF RELIEF IMAGES BY HORIZONTALS

On topographic maps, the relief is depicted by contour lines, i.e., curved closed lines, each of which is an image on the map of a horizontal contour of unevenness, all points of which on the ground are located at the same height above sea level.
In order to better understand the essence of the depiction of the relief by contour lines, let us imagine an island in the form of a mountain gradually flooded with water. Let us assume that the water level successively stops at equal intervals in height, equal to h meters (Fig. 9.2).

Rice. 9.2. The essence of the image of the relief by contour lines

For each water level, starting from the initial ( AB) will obviously match its coastline ( CD, KL, MN, RS) in the form of a closed curve, all points of which have the same height.
These lines can also be considered as traces of the section of uneven terrain by level surfaces parallel to the level surface of the sea, from which the heights are calculated. Based on this, the distance h in height between adjacent secant surfaces is called section height.
If all these lines of equal heights are projected onto the surface of the earth's ellipsoid and depicted on a map on a given scale, then we will get an image of a mountain on it in plan in the form of a system of closed curved lines ab, cd, kl, tp and rs. These will be horizontal.
Considering the essence of horizontals, we can draw the following conclusion:
a) each contour on the map is a horizontal projection of a line of equal heights on the ground, depicting the planned outline of the unevenness of the earth's surface. Thus, according to the pattern and the mutual position of the horizontals, one can perceive the forms, the mutual position and the relationship of irregularities;
b) since the contour lines on the map are drawn at regular intervals in height, then by the number of contour lines on the slopes it is possible to determine the height of the slopes and the mutual excess of points on the earth's surface: the more contour lines on the slope, the higher it is;
in) laying horizontal lines , i.e. distances in plan between adjacent horizontals, depend on the steepness of the slope: the steeper the slope, the less the laying. Therefore, by the magnitude of the foundation, one can judge the steepness of the slope.

9.3. TYPES OF HORIZONTALS

Section height relief on the map depends on scale cards and character relief. For flat and hilly terrain, its value is equal to 0.02 of the map scale value (for example, on maps of scales 1:50,000 and 1:100,000, the normal section height is 10 and 20 m, respectively). On maps of high-mountainous regions, so that the image of the relief is not obscured due to excessive density of contour lines and is better readable, the height of the section is taken twice as normal (on a map of a scale of 1:25,000 - 10 m, 1:50,000 - 20 m, 1:100,000 - 40 m, 1:200,000 - 80 m). On maps of flat-plain regions at scales of 1:25,000 and 1:200,000, the height of the section is taken to be half the normal height, i.e., 2.5 and 20 m, respectively.
Contours on the map corresponding to the height of the section set for it are drawn solid lines and are called main , or solid , contour lines (Fig. 9.3).
It often happens that important details of the relief are not expressed on the map by the main horizontal lines. In these cases, in addition to the main horizontals, half (semi-horizontals ), which are drawn on the map through half the main height of the section. Unlike the main ones, half horizontals are drawn with broken lines.
In some places, where the necessary details of the relief are not expressed by the main and half contour lines, more lines are drawn between them. auxiliary horizontal - about quarter heights sections. They are also drawn with broken lines, but with shorter links.

Rice. 9.3. Main, half and auxiliary horizontals

To facilitate the calculation of contour lines when determining the heights of points on the map all solid contour lines corresponding to fivefold section height, draw a thickened line ( thickened horizontal).
The main height of the section is indicated on each sheet of the map - under the southern side of its frame. For example, the inscription "Solid contour lines are drawn through 10 m" means that on this sheet all the horizontal lines shown by solid lines are a multiple of 10 m, and thickened ones are a multiple of 50 m.

9.4. IMAGE OF HORIZONTALS OF ELEMENTARY FORMS OF RELIEF

On fig. 9.4. elementary relief forms are shown separately by horizontal lines. The figure shows that a small mountain (hill) and a hollow look, in general, the same - in the form of a system of closed contour lines encircling each other. The images of the ridge and the hollow are similar to each other. They can only be distinguished by the direction of the slopes.

Rice. 9.4. Image by contour lines
elementary landforms

Slope direction indicators, or berghashes , serve as short dashes, arranged horizontally (perpendicular to them) in the direction of slopes. They are placed on the curves of contour lines in the most characteristic places, mainly at the peaks, saddles or at the bottom of the basins, as well as on gentle slopes - in places that are difficult to read.
They also help determine the direction of the slopes. elevations on maps:

contour lines , i.e., digital signatures on some horizontal lines, indicating in meters their height above sea level. The top of these figures is always facing upward slope;
elevation marks individual, most characteristic points of the terrain - the tops of mountains and hills, the highest points of watersheds, the lowest points of valleys and ravines, water levels (cuts) in rivers and other reservoirs, etc.

On maps of a scale of 1:100,000 and larger, the elevations of points above sea level are signed with an accuracy of 0.1 m, and on maps of 1:200,000 and smaller - to whole meters. This must be kept in mind in order not to confuse points when indicating and identifying their marks on maps of different scales.

9.5. FEATURES OF IMAGES OF PLAIN AND MOUNTAIN RELIEF BY HORIZONTALS

Irregularities with large, clearly defined and smooth forms are most clearly represented by horizontal lines. The image of a flat relief is less expressive, since the horizontals here pass at a considerable distance from one another and do not express many details that lie between the horizontals of the main section. Therefore, along with the main (solid) contour lines, semi-horizontal lines are widely used on maps of flat regions. This improves the readability and detail of flat relief images. When studying such a relief and determining its numerical characteristics from the map, one must be especially careful not to confuse the half and auxiliary horizontals with the main ones.
When studying a mountainous and strongly rugged relief on a map, on the contrary, one has to deal with a very dense arrangement of contour lines. With a large steepness of the slopes, the laying in some places is so small that it is not possible to draw all the horizontals here separately.
Therefore, when depicting slopes on maps, the steepness of which is greater than the limiting one, the horizontals are drawn together one with the other or with a dotted line, leaving only two or three intermediate horizontals between the thickened horizontals instead of four. In such places, when determining the heights of points or the steepness of slopes on a map, thickened contour lines should be used.

9.6. CONVENTIONAL SIGNS OF RELIEF ELEMENTS NOT EXPRESSED IN HORIZONTALS

Objects and relief details that cannot be depicted by contour lines (more than 45º) are shown on maps with special conventional symbols (Fig. 9.5).

Rice. 9.5. Relief symbols

Such objects include cliffs, rocks, scree, ravines, gullies, ramparts, road embankments and cuts, mounds, pits, sinkholes. The numbers accompanying the symbols of these objects indicate their relative heights (depths) in meters.
Conventional signs of natural relief formations and the signatures of characteristics related to them, as well as horizontal lines, are printed in brown ink, and artificial ones (embankments, excavations, barrows, etc.) are printed in black.

Rice. 9.6. Fortified field terraces (figures - heights in meters)

Rice. 9.7. Mounds (numbers - heights in meters):
a) - on the cards; b - on the plans

The following are depicted by special conventional black symbols: remnant rocks - large separately lying stones and clusters of stones, which are landmarks, indicating their relative heights; caves, grottoes and underground workings with their numerical characteristics (in the numerator - the average diameter of the entrance, in the denominator - the length or depth in meters); tunnels indicating their height and width in the numerator, and their length in the denominator. On roads and trails crossing mountain ranges, passes are marked with an indication of their height above sea level and the time of action.
The relief of eternal snows (firn fields) and glaciers is also depicted by horizontal lines, but in blue. The same color shows all the symbols related to it (ice cliffs, ice cracks, icing) and numerical marks of heights and contours.

Rice. 9.8. The relief of eternal snows and glaciers
a) firn fields (eternal snows), b) glaciers, c) glacial cracks, d) moraines, e) stone rivers. e) stony placers. g) rocks and rocky cliffs, h) steep slopes less than 1 cm long on the map. i) steep slopes more than 1 cm long on the map. j) borders of firn fields

9.7. PECULIARITIES OF RELIEF DISPLAY ON MAP SCALE 1:500,000 AND 1:1,000,000

The relief on small-scale topographic maps, as well as on maps of larger scales, is depicted by contour lines and conventional signs, but more generally. They display only the general nature of the relief - its structure, main forms, the degree of its vertical and horizontal dissection.
The height of the main section when depicting flat areas on both maps is set to 50 m, and mountainous - 100 m. On a map of a scale of 1: 1,000,000, in addition, a section height of 200 m is used to depict areas located above 1,000 m above sea level .
Relief objects that are not expressed as contour lines are shown only those that are necessary to characterize the terrain or are important landmarks. They are marked with the same symbols as on other maps, but smaller.
The main feature is the depiction of mountainous terrain. For greater clarity, its image is supplemented by horizontal lines with the so-called laundering and layered coloring book by the heights.

Rice. 9.9. Map without hillshade (top) and with hillshade (bottom)

laundering , i.e. shading of the slopes of the most important forms of mountainous relief, makes the image more expressive and plastic, allowing you to visually feel its three-dimensional forms. Shading is done with gray-brown paint according to the principle - the more significant, higher and steeper the slope, the stronger the tone of the hillshade.
Thanks to hillshading, the main mountain ranges and massifs, their most important spurs and peaks, passes, ledges of highlands, deep valleys and canyons are well distinguished. The direction and comparative steepness of the slopes, the shape of the ridges (sharp, rounded, etc.) and the difference in height of the main mountain ranges are clearly perceived.
Layered coloring by height steps visually displays the high-altitude characteristics of the mountainous relief and enhances the plastic effect of its image. It is performed with orange paint of various tones according to the principle - the higher, the darker. In this case, the image of the relief is, as it were, divided into separate high-altitude layers (steps), according to the color tone of which their absolute heights and mutual excesses are easily distinguished. The color tone of the layers intensifies after 400, 600 or 1000 m, depending on their absolute heights. The scale of elevation steps adopted on the map is indicated on each sheet under the southern side of its frame.

Questions and tasks for self-control

Give the definition of "relief", "horizontal", "sectional height", "laying", "laying a slope"
Name the main forms of the part and relief elements, give them a brief description.
What are the main horizontal lines?
For what purposes are half and auxiliary horizontals used and at what vertical distance are they drawn on the map?
What is the purpose of the berghstres on the map?
What colors are used to depict relief on maps?
What is the essence of the hillshade method for depicting relief on maps?
What is the essence of the hypsometric method for depicting relief on maps?
How are the digital designations located at the signatures of the contour lines?
What relief features are marked on the maps with special symbols?
With the help of contour lines, show in the drawing a mountain, a ridge, a saddle, a basin, a hollow.
What are the features of the relief image by contour lines on flat and mountainous terrain?
Name the types of slopes. How are they shown on the maps?
What are the features of the relief image on maps of scales 1:1,000,000 and 1:500,000?

The structure of the earth's surface is very diverse. However, it is always possible to find forms that are similar in appearance and origin, which are regularly repeated in a certain territory and are typical for it. Such combinations of forms of the earth's surface that are homogeneous in appearance and origin are called relief types.

The main external features of the relief: the nature of its forms, height above sea level and the relative height or depth of dissection. According to these indicators, the relief is flat, hilly and mountainous.

Plains called areas in which the fluctuations in heights and slopes of the surface are very small.

Plains are: oblique- with a slight slope to one side; concave- with an inclination from all sides to the middle; and wavy- with fluctuations in inclination, then in one direction, then in the other direction and alternating flat elevations and elevations of the surface.

According to the height above sea level, the following plains are conditionally distinguished:

– base- with an absolute height of up to 200 m;

– sublime(plateau) - with heights up to 500 m;

– upland- with altitudes over 500 m.

hilly they call a relief with relative heights up to 200 m. Hills often have the form of elongated ridges or ridges and, accordingly, form a ridge or hilly relief. Depending on the height of the hills, the relief is distinguished coarse-hilly, medium hilly and small hilly.

Mountain a relief is called, the irregularities of which exceed the relative height of 200 m. According to the shape, absolute and relative height, the mountain relief is divided into the following types: alpine(alpine) type, mid-mountain and lowland types.

The morphology of the plain, hilly and mountainous relief is far from exhausted by the above characteristics. It is largely determined by the features of the geomorphological structure of the territory and, above all, by the conditions of occurrence of rocks.

The following four forms of bedding are most characteristic:

undisturbed horizontal occurrence;

slightly disturbed horizontal occurrence - the layers have a gentle and consistent fall;

folded occurrence - layers are crumpled into folds;

fold-fault occurrence - the layers are crumpled into folds and displaced relative to each other.

The nature of the occurrence of layers finds a vivid expression in the forms of relief during their erosional dissection, and especially in those cases where there is an alternation of layers of different density and different resistance to erosion.

Such specific forms of relief, due to the occurrence of layers of different densities, i.e. geological structure are called structural.

Under conditions of undisturbed horizontal occurrence of layers, erosional dissection forms watershed elevations (plateaus, plateaus). The slopes of the hill are often stepped, each step corresponds to the exit to the surface of a solid layer.

Under conditions of weakly disturbed layers during erosional dissection, in places where dense layers emerge, characteristic structural relief forms are formed, called cuestami. They are usually separated by valleys embedded in softer, more easily eroded rocks. Cuesta usually have an asymmetrical structure.

Under conditions of folded occurrence, with the alternation of regular folds of a convex (anticline) and concave (syncline) shape, erosional dissection most often forms anticlinal ridges with a wide rounded ridge, monoclinal ridges with a sharp ridge and an asymmetric transverse profile; longitudinal synclinal valleys with a symmetrical transverse profile; asymmetric monoclinal valleys.

Under the conditions of folded-faulting occurrence of layers, in addition to the listed relief forms, there are also forms that were formed as a result of vertical displacements of layers (uplifts and subsidence) with gaps between them. Are formed horsts and grabens. The latter in the mountains are usually occupied by rivers and lakes, contoured by small steps and slopes with ledges.

Thus, the geological structure of the area determines the formation of various and widespread structural forms characteristic of various types of relief. From this it follows that even a general idea of the geological structure of the region is of considerable help in assessing the image of the relief on a topographic map.

The relief of the earth's surface is determined not only by the movement of the earth's crust (tectonics) and the nature of the occurrence of layers, but also by the activity of the second group of factors - external (exogenous). The latter significantly transform the primary (tectonic) forms and greatly complicate their structure.

These factors include the activity of water flows (temporary and permanent) of the seas, lakes, glaciers, melted glacial waters, groundwater, wind and others. The activity of these factors is manifested in the fact that in some places the rocks lying on the surface of the Earth are destroyed, eroded and carried out from the given area to another, where they are deposited and, accumulating, often reach great thickness, thus passing through the stages of hypergenesis, sedimentogenesis and diagenesis.

The processes of destruction are called erosion(or more broadly denudation), and accumulations - accumulations. In the process of erosion or denudation, the relief is dissected, the elevations are more and more destroyed and eventually leveled out (the process peneplanization). Such relief is called erosion or denudation.

In the process of accumulation, depressions are filled with loose rocks carried from the side, and a predominantly flat relief, called accumulative, is formed.

In accordance with what factor (agent) produces erosion or accumulation, water-erosion or water-accumulation forms, glacial-erosion and glacial-accumulation forms, etc. are distinguished.

Where the activity of surface and underground waters occurs in soluble rocks (limestones, dolomites, etc.), peculiar voids (karst landforms) are formed.

The flat, hilly and mountainous reliefs described above can be of different origin and, consequently, have different forms.

Plains by their origin are:

– marine accumulative- formed as a result of transgression of the ocean floor;

– river accumulative- are formed as a result of tectonic uplifts and subsidences;

– water-glacial accumulative- formed as a result of melting glaciers;

- lacustrine-accumulative - areas of flat bottoms of former lakes;

- upland accumulative - are formed as a result of the destruction and accumulation of materials;

– volcanic- the result of the activity and destruction of volcanoes;

- residual - the result of denudation of the earth's surface;

- abrasion - the result of the impact of sea waves.

Hilly relief by origin is: water-erosion; glacial erosion; wind and volcanic.

Mountain relief by origin is: erosion-tectonic, erosion (erosion-folded and erosion-block) and volcanic.

1.1 Types and landforms

In military affairs terrain understand the area of the earth's surface on which to conduct hostilities. The unevenness of the earth's surface is called terrain, and all objects located on it, created by nature or human labor (rivers, settlements, roads, etc.) - local items.

The relief and local objects are the main topographical elements of the terrain that affect the organization and conduct of combat, the use of military equipment in combat, the conditions for observation, firing, orientation, camouflage and maneuverability, i.e., determining its tactical properties.

A topographic map is an accurate representation of all the most tactically important elements of the terrain, plotted in a mutually exact arrangement relative to each other. It makes it possible to explore any territory in a relatively short time. Preliminary study of the terrain and decision-making for the performance of a particular combat mission by a subunit (unit, formation) is usually carried out on a map, and then refined on the ground.

The terrain, influencing combat operations, in one case can contribute to the success of the troops, and in the other have a negative effect. Combat practice convincingly shows that one and the same terrain can give more advantages to those who study it better and use it more skillfully.

According to the nature of the relief, the area is divided into flat, hilly and mountainous.

flat terrain characterized by small (up to 25 m) relative elevations and a relatively small (up to 2 °) steepness of slopes. Absolute heights are usually small (up to 300 m) (Fig. 1).

Rice. 1. Flat, open, slightly rugged terrain

Flat terrain is usually more favorable for the organization and conduct of an offensive and less favorable for defense.

Rice. 2. Plain lake-forest closed rugged terrain

Rice. 3. Hilly semi-closed rugged terrain

Rice. 4. Hilly ravine-beam semi-closed rugged terrain

Mountain landscape represents areas of the earth's surface that are significantly elevated above the surrounding area (having absolute heights of 500 m or more) (Fig. 5). It is distinguished by a complex and varied relief, specific natural conditions. The main landforms are mountains and mountain ranges with steep slopes, often turning into rocks and rocky cliffs, as well as hollows and gorges located between mountain ranges. The mountainous area is characterized by a sharp rugged terrain, the presence of hard-to-reach areas, a sparse network of roads, a limited number of settlements, a rapid flow of rivers with sharp fluctuations in water levels, a variety of climatic conditions, and a predominance of rocky soils.

Combat operations in mountainous areas are considered as operations in special conditions. Troops often have to use mountain passes; observation and firing, orientation and target designation are difficult, at the same time it contributes to the secrecy of the location and movement of troops, facilitates the setting up of ambushes and engineering barriers, and the organization of camouflage.

Rice. 5. Mountainous rugged terrain

1.2 The essence of the image of the relief on maps by contour lines

The relief is the most important element of the terrain, which determines its tactical properties.

The image of the relief on topographic maps gives a complete and sufficiently detailed idea of the irregularities of the earth's surface, the shape and relative position, elevations and absolute heights of terrain points, the prevailing steepness and length of slopes.

Rice. 6. The essence of the image of the relief by contour lines

The relief on topographic maps is depicted by horizontal lines in combination with conventional signs of cliffs, rocks, ravines, gullies, stone rivers, etc. The image of the relief is supplemented by elevation marks of characteristic points of the area, contour lines, relative heights (depths) and slope direction indicators (bergstrokes) . On all topographic maps, the relief is depicted in the Baltic system of heights, that is, in the system of calculating absolute heights from the average level of the Baltic Sea.

1.3 Types of contour lines

Horizontal- a closed curved line on the map, which corresponds to a contour on the ground, all points of which are located at the same height above sea level.

There are the following horizontal lines:

main(solid) - relief section corresponding to the height;
thickened - every fifth main horizontal; stands out for ease of reading the relief;
d additional horizontals(semi-horizontals) - are drawn by a broken line at the height of the relief section equal to half of the main one;
auxiliary - are depicted as short dashed thin lines, at an arbitrary height.

To facilitate the calculation of contour lines when determining the heights of points on the map, all solid contour lines corresponding to the fifth multiple of the height of the section are drawn thickened and a number indicating the height above sea level is put on it.

In order to quickly determine the nature of surface irregularities on maps when reading a map, special slope direction indicators are used - berghashes- in the form of short dashes placed on the horizontals (perpendicular to them) in the direction of the slopes. They are placed on the bends of contour lines in the most characteristic places, mainly at the tops of saddles or at the bottom of basins.

Additional contours(semi-horizontals) are used to display the characteristic forms and details of the relief (bends of slopes, peaks, saddles, etc.), if they are not expressed by the main horizontals. In addition, they are used to depict flat areas, when the laying between the main contours is very large (more than 3 - 4 cm on the map).

Auxiliary horizontals used to depict individual details of the relief (saucers in the steppe regions, depressions, individual hillocks on flat terrain), which are not transmitted by the main or additional horizontals.

1.4 Depiction by contour lines of typical landforms

The relief on topographic maps is depicted by curved closed lines connecting points of the terrain that have the same height above the level surface, taken as the origin of the heights. Such lines are called horizontal lines. The image of the relief with contour lines is supplemented by labels of absolute heights, characteristic points of the terrain, some contour lines, as well as numerical characteristics of relief details - height, depth or width (Fig. 7).

Rice. 7. Representation of the relief by conventional signs

Some typical forms of terrain on the maps are displayed not only by the main, but also by additional and auxiliary contour lines (Fig. 8).

Rice. 8. Image of typical landforms

2. Determination on the map of absolute heights and relative elevations of terrain points, ascents and descents, steepness of slopes

2.1. Determination on the map of absolute heights and relative elevations of terrain points

Rice. 9. Determination on the map of absolute heights of relative elevations of terrain points

Altitude- height of a point on the earth's surface above sea level; is determined by the heights and contour lines (in Fig. 9, these are the heights with marks 33.1 and 49.8).

Relief section height- the distance in height between two adjacent cutting planes.

Relative height(mutual excess of points)- the height of a terrain point above another, it is defined as the difference in the absolute heights of these points (in Fig. 9, the relative height is 16.7 (49.8-33.1)).

Rice. 10. Definition on the map of ascents and descents on the route of movement (route profile).

Rice. 11. Determination on the map of the steepness of the slopes

Profile- a drawing depicting a section of the terrain with a vertical plane.

For greater expressiveness of the terrain, the vertical scale of the profile is taken 10 or more times larger than the horizontal one.

In this regard, the profile, transmitting the mutual excess of points, distorts (increases) the steepness of the slopes.

To build a profile, you need(Fig. 10) :

draw a profile line (travel route) on the map, attach a sheet of graphed (millimetric) paper to it, transfer to its edge with short lines the places of contour lines, the inflection points of the slopes and local objects that the profile line cuts, and sign their heights;
sign on a sheet of graphed paper at the horizontal lines the heights corresponding to the heights of the contour lines on the map, conventionally taking the gaps between these lines as the height of the section (set the vertical scale);
from all dashes indicating the intersections of the profile line with elevation marks of contour lines, inflection points of slopes and local objects, lower the perpendiculars until they intersect with parallel lines corresponding to the marks and mark the resulting intersection points;
connect the intersection points of a smooth curve, which will depict the terrain profile (ascents and descents on the route of movement).

The steepness of the slope on the map is determined by the location - the distance between two adjacent main or thickened horizontals; the smaller the laying, the steeper the slope.

To determine the steepness of the slope, it is necessary to measure the distance between the horizontals with a compass, find the corresponding segment on the laying chart and read the number of degrees (Fig. 11).