Map satellite view and measure distance. Measuring areas according to plan and map

1.1.Scales of maps

Map scale shows how many times the length of a line on a map is less than its corresponding length on the ground. It is expressed as a ratio of two numbers. For example, a scale of 1:50,000 means that all terrain lines are depicted on the map with a reduction of 50,000 times, i.e. 1 cm on the map corresponds to 50,000 cm (or 500 m) on the terrain.

Rice. 1. Design of numerical and linear scales on topographic maps and city plans

The scale is indicated under the bottom side of the map frame in digital terms (numerical scale) and in the form of a straight line (linear scale), on the segments of which the corresponding distances on the ground are labeled (Fig. 1). The scale value is also indicated here - the distance in meters (or kilometers) on the ground, corresponding to one centimeter on the map.

It is useful to remember the rule: if you cross out the last two zeros on the right side of the ratio, then the remaining number will show how many meters on the ground correspond to 1 cm on the map, i.e. the scale value.

When comparing several scales, the larger one will be the one with the smaller number on the right side of the ratio. Let's assume that there are maps of scales 1:25000, 1:50000 and 1:100000 for the same area. Of these, a scale of 1:25,000 will be the largest, and a scale of 1:100,000 will be the smallest.
The larger the scale of the map, the more detailed the terrain is depicted. As the scale of the map decreases, the number of terrain details shown on it also decreases.

The detail of the terrain depicted on topographic maps depends on its nature: what less details contains the terrain, the more fully they are displayed on maps of smaller scales.

In our country and many other countries, the main scales for topographic maps are: 1:10000, 1:25000, 1:50000, 1:100000, 1:200000, 1:500000 and 1:1000000.

The maps used by the troops are divided into large-scale, medium-scale and small-scale.

Map scale	Card name	Card classification
		by scale	for main purpose
1:10 000 (in 1 cm 100 m)	ten thousandth	large scale	tactical
1:25,000 (in 1 cm 250 m)	twenty-five thousandth
1:50,000 (in 1 cm 500 m)	five thousandth
1:100,000 (1 cm 1 km)	hundred thousandth	medium-scale
1:200,000 (in 1 cm 2 km)	two hundred thousandth		operational
1:500,000 (1 cm 5 km)	five hundred thousandth	small-scale
1:1 000 000 (1 cm 10 km)	millionth

1.2. Measuring straight and curved lines using a map

To determine on a map the distance between terrain points (objects, objects), using a numerical scale, you need to measure on the map the distance between these points in centimeters and multiply the resulting number by the scale value.

Example, on a map of scale 1:25000 we measure the distance between the bridge and the windmill with a ruler (Fig. 2); it is equal to 7.3 cm, multiply 250 m by 7.3 and get the required distance; it is equal to 1825 meters (250x7.3=1825).

Rice. 2. Determine the distance between terrain points on the map using a ruler.

A small distance between two points in a straight line is easier to determine using a linear scale (Fig. 3). To do this, a measuring compass is sufficient, the solution of which equal to the distance between given points on the map, apply it to a linear scale and take a reading in meters or kilometers. In Fig. 3 the measured distance is 1070 m.

Rice. 3. Measuring distances on a map with a measuring compass on a linear scale

Rice. 4. Measuring distances on a map with a compass along winding lines

Large distances between points along straight lines are usually measured using a long ruler or measuring compass.

In the first case, a numerical scale is used to determine the distance on the map using a ruler (see Fig. 2).

In the second case, the “step” solution of the measuring compass is set so that it corresponds to an integer number of kilometers, and an integer number of “steps” is plotted on the segment measured on the map. The distance that does not fit into the whole number of “steps” of the measuring compass is determined using a linear scale and added to the resulting number of kilometers.

In the same way, distances are measured along winding lines (Fig. 4). In this case, the “step” of the measuring compass should be taken 0.5 or 1 cm, depending on the length and degree of tortuosity of the line being measured.

Rice. 5. Distance measurements with a curvimeter

To determine the length of a route on a map, a special device is used, called a curvimeter (Fig. 5), which is especially convenient for measuring winding and long lines.

The device has a wheel, which is connected by a gear system to an arrow.

When measuring distance with a curvimeter, you need to set its needle to division 99. Holding the curvimeter in a vertical position, move it along the line being measured, without lifting it from the map along the route so that the scale readings increase. Having reached the end point, count the measured distance and multiply it by the denominator of the numerical scale. (IN in this example 34x25000=850000, or 8500 m)

1.3. Accuracy of measuring distances on the map. Distance corrections for slope and tortuosity of lines

Accuracy of determining distances on the map depends on the scale of the map, the nature of the measured lines (straight, winding), the chosen measurement method, the terrain and other factors.

The most accurate way to determine the distance on the map is in a straight line.

When measuring distances using a compass or a ruler with millimeter divisions average value measurement errors in flat areas usually do not exceed 0.7-1 mm at the map scale, which is 17.5-25 m for a map of scale 1:25000, 35-50 m for a map of scale 1:50000, 35-50 m for a map of scale 1:100000. 70-100 m.

In mountainous areas with steep slopes, errors will be greater. This is explained by the fact that when surveying a terrain, it is not the length of the lines on the Earth’s surface that is plotted on the map, but the length of the projections of these lines onto the plane.

For example, With a slope steepness of 20° (Fig. 6) and a distance on the ground of 2120 m, its projection onto the plane (distance on the map) is 2000 m, i.e. 120 m less.

It is calculated that with an inclination angle (steepness of the slope) of 20°, the resulting distance measurement result on the map should be increased by 6% (add 6 m per 100 m), with an inclination angle of 30° - by 15%, and with an angle of 40° - by 23 %.

Rice. 6. Projection of the length of the slope onto a plane (map)

When determining the length of a route on a map, it should be taken into account that road distances measured on the map using a compass or curvimeter are in most cases shorter than the actual distances.

This is explained not only by the presence of ups and downs on the roads, but also by some generalization of road convolutions on maps.

Therefore, the result of measuring the length of the route obtained from the map should, taking into account the nature of the terrain and the scale of the map, be multiplied by the coefficient indicated in the table.

1.4. The simplest ways to measure areas on a map

An approximate estimate of the size of the areas is made by eye using the squares of the kilometer grid available on the map. Each grid square of maps of scales 1:10000 - 1:50000 on the ground corresponds to 1 km2, a grid square of maps of scale 1 : 100000 - 4 km2, the square of the map grid at a scale of 1:200000 - 16 km2.

Areas are measured more accurately palette, which is a sheet of transparent plastic with a grid of squares with a side of 10 mm applied to it (depending on the scale of the map and the required measurement accuracy).

Having applied such a palette to the measured object on the map, they first count from it the number of squares that completely fit inside the contour of the object, and then the number of squares intersected by the contour of the object. We take each of the incomplete squares as half a square. As a result of multiplying the area of one square by the sum of squares, the area of the object is obtained.

It is convenient to measure the areas of small areas using squares of scales 1:25000 and 1:50000 officer's line, having special rectangular cutouts. The areas of these rectangles (in hectares) are indicated on the ruler for each gharta scale.

2. Azimuths and directional angle. Magnetic declination, convergence of meridians and direction correction

True azimuth(Au) - horizontal angle, measured clockwise from 0° to 360° between the northern direction of the true meridian of a given point and the direction to the object (see Fig. 7).

Magnetic azimuth(Am) - horizontal angle, measured clockwise from 0e to 360° between the northern direction of the magnetic meridian of a given point and the direction to the object.

Directional angle(α; DU) - horizontal angle measured clockwise from 0° to 360° between the north direction of the vertical line grid given point and direction to the object.

Magnetic declination(δ; Sk) - the angle between the northern direction of the true and magnetic meridians at a given point.

If the magnetic needle deviates from the true meridian to the east, then the declination is eastern (counted with a + sign); if the magnetic needle deviates to the west, then the declination is western (counted with a - sign).

Rice. 7. Angles, directions and their relationships on the map

Meridian convergence(γ; Sat) - the angle between the northern direction of the true meridian and the vertical grid line at a given point. When the grid line deviates to the east, the convergence of the meridian is eastern (counted with a + sign), when the grid line deviates to the west - western (counted with a - sign).

Direction correction(PN) - the angle between the northern direction of the vertical grid line and the direction of the magnetic meridian. It is equal algebraic difference magnetic declination and convergence of meridians:

3. Measuring and plotting directional angles on the map. Transition from directional angle to magnetic azimuth and back

On the ground using a compass (compass) to measure magnetic azimuths directions, from which they then move to directional angles.

On the map on the contrary, they measure directional angles and from them they move on to magnetic azimuths of directions on the ground.

Rice. 8. Changing directional angles on the map with a protractor

Directional angles on the map are measured with a protractor or chord angle meter.

Measuring directional angles with a protractor is carried out in the following sequence:

the landmark at which the directional angle is measured is connected by a straight line to the standing point so that this straight line is greater than the radius of the protractor and intersects at least one vertical line of the coordinate grid;
align the center of the protractor with the intersection point, as shown in Fig. 8 and count the value of the directional angle using the protractor. In our example, the directional angle from point A to point B is 274° (Fig. 8, a), and from point A to point C is 65° (Fig. 8, b).

In practice, there is often a need to determine the magnetic AM from a known directional angle ά, or, conversely, the angle ά from a known magnetic azimuth.

Transition from directional angle to magnetic azimuth and back

The transition from the directional angle to the magnetic azimuth and back is carried out when on the ground it is necessary to use a compass (compass) to find the direction whose directional angle is measured on the map, or vice versa, when it is necessary to put on the map the direction whose magnetic azimuth is measured on the ground with using a compass.

To solve this problem, it is necessary to know the deviation of the magnetic meridian of a given point from the vertical kilometer line. This value is called the direction correction (DC).

Rice. 10. Determination of the correction for the transition from directional angle to magnetic azimuth and back

The direction correction and its constituent angles - the convergence of meridians and magnetic declination are indicated on the map under the southern side of the frame in the form of a diagram that looks like that shown in Fig. 9.

Meridian convergence(g) - the angle between the true meridian of a point and the vertical kilometer line depends on the distance of this point from the axial meridian of the zone and can have a value from 0 to ±3°. The diagram shows the average convergence of meridians for a given map sheet.

Magnetic declination(d) - the angle between the true and magnetic meridians is indicated on the diagram for the year the map was taken (updated). The text placed next to the diagram provides information about the direction and magnitude of the annual change in magnetic declination.

To avoid errors in determining the magnitude and sign of the direction correction, the following technique is recommended.

From the tops of the corners in the diagram (Fig. 10), draw an arbitrary direction OM and designate with arcs the directional angle ά and the magnetic azimuth Am of this direction. Then it will be immediately clear what the magnitude and sign of the direction correction are.

If, for example, ά = 97°12", then Am = 97°12" - (2°10"+10°15") = 84°47 " .

4. Preparation according to the data map for movement in azimuths

Movement in azimuths- This is the main way to navigate in areas poor in landmarks, especially at night and with limited visibility.

Its essence lies in maintaining on the ground the directions specified by magnetic azimuths and the distances determined on the map between the turning points of the intended route. Directions of movement are determined using a compass, distances are measured in steps or using a speedometer.

The initial data for movement along azimuths (magnetic azimuths and distances) are determined from the map, and the time of movement is determined according to the standard and drawn up in the form of a diagram (Fig. 11) or entered into a table (Table 1). Data in this form is given to commanders who do not have topographic maps. If the commander has his work card, then he draws up the initial data for movement along azimuths directly on the working map.

Rice. 11. Scheme for movement in azimuth

The route of movement along azimuths is chosen taking into account the terrain's passability, its protective and camouflage properties, so that in a combat situation it provides a quick and covert exit to the specified point.

The route usually includes roads, clearings and other linear landmarks that make it easier to maintain the direction of movement. Turning points are chosen at landmarks that are easily recognizable on the ground (for example, tower-type buildings, road intersections, bridges, overpasses, geodetic points, etc.).

It has been experimentally established that the distances between landmarks at turning points of the route should not exceed 1 km when traveling on foot during the day, and 6–10 km when traveling by car.

For driving at night, landmarks are marked along the route more often.

To ensure a secret exit to a specified point, the route is marked along hollows, tracts of vegetation and other objects that provide camouflage of movement. Avoid traveling on high ridges and open areas.

The distances between landmarks chosen along the route at turning points are measured along straight lines using a measuring compass and a linear scale, or, perhaps more accurately, with a ruler with millimeter divisions. If the route is planned along a hilly (mountainous) area, then a correction for the relief is introduced into the distances measured on the map.

Table 1

5. Compliance with standards

No. norm.	Name of the standard	Conditions (procedure) for compliance with the standard	Category of trainees	Estimation by time
No. norm.	Name of the standard	Conditions (procedure) for compliance with the standard	Category of trainees	"excellent"	"choir."	"ud."
1	Determining direction (azimuth) on the ground	The direction azimuth (landmark) is given. Indicate the direction corresponding to a given azimuth on the ground, or determine the azimuth to a specified landmark. The time to fulfill the standard is counted from the statement of the task to the report on the direction (azimuth value). Compliance with the standard is assessed “unsatisfactory” if the error in determining the direction (azimuth) exceeds 3° (0-50).	Serviceman	40 s	45 s	55 s
5	Preparing data for azimuth movement	The M 1:50000 map shows two points at a distance of at least 4 km. Study the area on a map, outline a route, select at least three intermediate landmarks, determine directional angles and distances between them. Prepare a diagram (table) of data for movement along azimuths (translate directional angles into magnetic azimuths, and distances into pairs of steps). Errors that reduce the rating to “unsatisfactory”: the error in determining the directional angle exceeds 2°; the error in distance measurement exceeds 0.5 mm at the map scale; corrections for the convergence of meridians and the declination of the magnetic needle are not taken into account or incorrectly introduced. The time to fulfill the standard is counted from the moment the card is issued to the presentation of the diagram (table).	Officers	8 min	9 min	11 min

Download from Depositfiles

METHODOLOGICAL INSTRUCTIONS FOR LABORATORY WORK

ON THE COURSE “GEODESY Part 1”

7. MEASUREMENT OF AREA ACCORDING TO PLAN OR MAP

To solve a number of engineering problems, it is necessary to determine the areas of various areas of the terrain from a plan or map. The determination of areas can be done graphically. analytical and mechanical methods.

7.1. Graphical method for determining area

The graphical method is used to determine small areas (up to 10-15 cm2) from a plan or map and is used in two versions: a) with a breakdown of the intended area into geometric figures; b) using palettes.

In the first option, the area of the site is divided into the simplest geometric figures: triangles, rectangles, trapezoids (Fig. 19, a), the corresponding elements of these figures are measured (base lengths and heights) and the areas of these figures are calculated using geometric formulas. The area of the entire plot is determined as the sum of the areas of individual figures. The division of the area into figures should be done in such a way that the figures can be large sizes, and their sides coincided as closely as possible with the contour of the site.

To control, the area of the site is divided into other geometric shapes and the area is re-determined. The relative discrepancy in the results of double determinations of the total area of the site should not exceed 1: 200.

For small areas (2-3 cm 2) with clearly defined curved boundaries, it is advisable to determine the area using using a square palette(Fig. I9, b). The palette can be made on tracing paper by drawing it with a grid of squares with sides of 2-5 mm. Knowing the length of the side and the scale of the plan, you can calculate the area of the square of the palette I KB.

To determine the area of the site, the tent is randomly placed on the plan and the number of complete squares is counted N 1 , located inside the contour of the site. Then evaluate each incomplete square by eye (in tenths) and find the total number N 2 for all incomplete squares on the boundaries of the contour. Then total area measured area S= s KB *(N 1 + N 2 ). For control, the tent is deployed approximately 45 A and the area is re-determined. The relative error in determining the area with a square palette is 1: 50 - 1: 100. When determining areas, several larger areas (up to 10 cm2) can be used linear palette(Fig. 19, c), which can be made on tracing paper by drawing a series of parallel lines at equal intervals (2-5 mm). The palette is applied to this area in such a way that extreme points section (points m and n in Fig. 19, c) are located in the middle between parallel lines palettes. Then measure the length of the lines using compasses and a scale ruler. l 1 , l 2 ….., l n , which are the middle lines of the trapezoid into which the area of a given area is divided using a palette. Then the area of the plot S= a(l 1 + l 2 +……+ l n ), Where a- linear palette step, i.e. distance between parallel lines. For control, the palette is drawn at 60-90° relative to the original position and the area of the area is re-determined. The relative error in determining the area by a linear tent depends on its pitch and is 1: 50 - 1: 100
7.2. Analytical method for determining area If you collect enough points along the contour of the area of the measured area to approximate this area with the required accuracy by a polygon formed by these points (Fig. 19, a), and then measure the coordinates on the map X And at all points, then the area of the site can be determined analytically. For a polygon about the number of vertices n when they are digitized clockwise, the area will be determined by the formulas To control the calculations, the calculations are performed using both formulas. The accuracy of the analytical method depends on the density of the set of points along the contour of the measured area. With a significant number of points, it is advisable to carry out calculations using computers or microcalculators = 7.3. Mechanical method determining the area using a planimeter A planimeter is a mechanical device for measuring area. In engineering and geodetic practice, using a planimeter, the areas of fairly large areas are measured from plans or maps. Of the many designs of planimeters greatest distribution received polar planimeters. The polar planimeter (Fig. 20) consists of two levers - pole 1 and bypass 4. At the bottom of the weight 2, attached to one of the ends of the pole lever, there is a needle - the planimeter pole. At the second end of the pole lever there is a pin with a spherical head, which is inserted into a special socket in carriage 5 of the bypass lever. At the end of the bypass lever there is a lens 3, on which there is a circle with a bypass point in the center. Carriage 5 has a counting mechanism, consisting of a counter of 6 whole revolutions of the counting wheel and the counting wheel itself 7. For readings on the counting wheel there is a special device - vernier 8. When tracing the contour of a section of the bypass lens 3, the rim of the counting wheel and roller 9 rolls or slides along the paper , forming, together with the contour point, three reference points of the planimeter. In modern planimeters, a carriage with a counting mechanism can move along the bypass lever, thereby changing its length, and be fixed in a new position. The circumference of the counting wheel is divided into 100 parts, every tenth stroke is digitized. The planimeter count consists of four digits: the first digit is the smaller digit of the revolution counter closest to the pointer (thousands divisions of the planimeter), the second and third digits are the hundreds and tens divisions on the counting wheel, preceding the zero stroke of the vernier; the fourth digit is the number of the vernier stroke, which coincides with the nearest stroke of the counting wheel (division unit). Before measuring the area of an area, the planimeter is installed on the map so that its pole is located outside the area being measured, and the pole and bypass arms form approximately a right angle. In this case, the place where the pole is secured is chosen so that during the detour of the entire figure, the angle between the bypass and pole levers is no less than 30° and no more than 150°. Having aligned the contour point of the planimeter with a certain starting point of the contour of the section, the initial reading is taken using the counting mechanism no and smoothly trace the entire contour clockwise. Returning to the starting point, take the final count n. Count difference ( n -no) expresses the area of a figure in planimeter divisions. Then the area of the measured area Where µ is the cost of dividing the planimeter, i.e. area corresponding to one planimeter division. To control and improve the accuracy of measurement results, the area of the site is measured at two positions of the planimeter pole relative to the counting mechanism: “pole left” and “pole right”. Before measuring areas, it is necessary to determine the division priceplanimeter µ. To do this, choose a figure whose area is ½ O known in advance (for example, one or more grid squares). In order to obtain higher accuracy this figure trace along the contour 4 times: 2 times in the “pole right” position and 2 times in the “pole left” position. For each round, the initial and final readings are taken and their difference is calculated (n i- n oi) . The discrepancies between the difference values for “pole right” and “pole left” should not exceed 2 divisions for a figure area of up to 200 division, 3 divisions - with a figure area from 200 to 2000 divisions and 4 divisions - with a figure area over 2000 divisions of the planimeter. If the discrepancies do not exceed acceptable values, then the average is calculated.difference of counts (n- no) Wedand calculate the price of dividing the planimeter using the formula / (n - n o ) Wed The division value is calculated with an accuracy of 3-4 significant figures. The table (p. 39) shows an example of recording the measurement results of the planimeter division price and determining the area of the site on the map. The accuracy of determining areas with a polar planimeter depends on the size of the measured areas. The smaller the area of the plot, the more relative error its definitions. It is recommended to use a planimeter to measure the areas of plots on the plan (map) of at least 10-12 cm 2. At favorable conditions measurements, the relative error in determining areas using a planimeter is approximately 1: 400. 8. DESCRIPTION OF THE CARD When carrying out engineering and geodetic surveys, drawing up technical documentation requires the performer to have a good knowledge of conventional signs and basic patterns of placement of natural objects (for example, mutual consistency of relief, hydrography, vegetation, settlements, road network, etc.). Often there is a need to describe certain areas of the map. To describe a map area, it is recommended to use the following scheme. I. Name (nomenclature) of the card. 2. Output: 2.1. Where, when and by whom was the map compiled and published? 2.2. What cartographic materials is it made from? 3.1. Map scale. 3.2. Longitude and latitude of the map frames. 3.3. Kilometer grid, frequency of its lines and their digitization. 3.4. Location on the map of the described area. 3.5. Geodetic basis on the described map (types of reference marks, their number). 4. Physiographic elements: hydrography (seas, rivers, lakes, canals, irrigation and drainage systems); relief, its character, dominant heights and lowest places, their marks; vegetation cover. 5. Socio-economic elements: settlements, transport routes, communications, industry, agriculture and forestry, cultural elements. As an example, the following description of one of the sections of the map at a scale of 1: 25,000 is given. I. Map U-34-37-V-v (Dreams). 2. Output: 2.1. The map was prepared for publication in 1981 by the GUGK and printed in 1982. Photographed by A.P. Ivanov. 2.2. The map was compiled based on materials from an aerial phototopographic survey of 1980. 3. Mathematical elements of the map: 3.1. Map scale 1: 25,000. 3.2. The map sheet is limited in longitude by the meridians 18 o 00' 00'' (in the west) and І8°07'"З0'' (in the east) and in latitude - by parallels 54 o 40' 00'' (in the south) and 54°45 '00'' (in the north). 3.3. The map shows a kilometer grid of rectangular coordinates (every 1 km). The grid squares on the map have side dimensions of 40 mm (on the map scale, 1 cm corresponds to 250 m on the ground). The map sheet contains 9 horizontal lines of the kilometer grid (from x = 6065 km in the south to x = 6073 km in the north) and 8 vertical lines grid (from y = 4307 km in the west to y = 4314 km in the east). 3.4. The described map area occupies four squares of the kilometer grid (from x 1 = 6068 km to x 2 = 6070 km and from y 1 = 4312 km to y 2 = 4314 km) east of the central map area. Determining the area of a plot using a planimeter

Pole position		Number			Counts				Difference r=n- n 0			Average r cp		Relative error (rpp- rpl)/ r cp		Value of division µ= s o/ r cp	Contour area S= µ * r cp
					n 0		n
1. Determination of the price of planimeter division (S o = 4 km 2 = 400 ha)
PP			2	0112 0243		6414 6549				6302 6306			6304	1:3152 0.06344 ha/division.
PL			2	0357 0481		6662 6788				6305 6307			6306
2. Determination of the area of the site
PP PL	2				0068 0106			0912 0952			846				1:472 0.06344 ha/division. 59.95 hectares

3.5. On the described section of the map there is one point of the geodetic network, installed on Mount Mikhalinskaya. 4. Physiographic elements. In the northeastern corner of the described area flows the Sot River, over 250 m wide. The direction of its flow is from northwest to southeast, the flow speed is 0.1 m/s. A permanent river bank signal sign has been installed on the western bank of the river. The banks of the river are swampy and covered with meadow vegetation. In addition, there are isolated bushes on the eastern bank of the river. In the area described, two streams flow into the Sot River, flowing along the bottom of ravines leading to the river. In addition to the indicated ravines, another ravine leads to the crayfish and in the southwestern part of the site there are two ravines covered with continuous vegetation. The terrain is hilly, with elevation differences of over 100 m. The dominant heights are Mount Bolshaya Mikhalinskaya with a peak elevation of 213.8 m in the western part of the site and Mount Mikhalinskaya with a peak elevation of 212.8 m in the southern part of the site. From these heights the relief rises towards the river (with a water mark of about 108.2 m). In the northern section the coast is steep (with a cliff height of up to 10 m). There is also a slight decrease in the relief from the indicated heights to the southwest. In the southern part of the site there is the Northern forest, occupying about 0.25 km 2 and located in the saddle between the indicated heights and to the east of the saddle. The predominant tree species in forest - pine, the average height of trees is about 20 m, the average thickness of trees is 0.20 m, the distance between trees is 6 m. In the southern part of the site, an area of open forest and cut down forest adjoins the Northern forest. On the western slope of Mount Mikhalinskaya there is a separate standing tree, having the value of a landmark. 5. Socio-economic elements. There are no settlements in the described area, but immediately beyond its borders in the southwest there is the settlement of Mikhalino, numbering 33 houses. The area of the site partly includes the gardens of this locality. There are three dirt (country) roads on the site. One of them runs from west to southwest of the site, the other goes from southwest to north and turns into a field road at the very edge of the site. At the point of this transition, the road branches and a third dirt road runs from north to southeast. local) road. From this third road in the southeast, another floor road branches off in a southerly direction. There are no other socio-economic elements in this area of the map.
9. PREPARATION OF THE REPORT Laboratory report on topographic map consists of an explanatory note and graphic documents. The explanatory note contains a write-off of the laboratory work performed and an explanation of the results obtained. The explanatory note is drawn up on separate sheets of writing paper (standard format 210 x 297 mm). Each laboratory work must have the name and information about the card on which it was performed, and the date the work was completed. The explanatory note must have title page, on which it is necessary to indicate the name of the faculty, group, the name of the student who completed the work, the name of the teacher who issued the assignment and checked the work, the date the work was completed. Graphic documents are a copy and a topographic profile. These documents are included in the explanatory note. A copy of the map is drawn in ink on tracing paper, and copies the border design of the map (design and degree frames, signatures), and the kilometer grid. Copies of those parts of the map that are necessary to illustrate the solution of a particular problem are also made onto a copy of the map on tracing paper, for example, when designing a line of a given slope, when determining the boundaries of a drainage area, when describing a section of the map. The topographic profile is drawn in ink on graph paper, and the profile line must be shown on a copy of the map and the horizontal lines directly adjacent (1 cm in each direction) to the profile line must be copied on it. Other graphic diagrams and drawings illustrating the solution of topographic map problems may be included in the text explanatory note. All drawings must be made carefully, without blots, in compliance with dimensions, symbols and fonts. The pages of the explanatory note must be numbered, and the note itself must have a table of contents. The count is submitted to the teacher for verification, after which it is defended by the student in class.

Very often, users are faced with a situation where they need to calculate the distance of a path. However, how and with what help to do this? The first thing that comes to mind is a navigator that can determine distance. However, the problem is that the navigator only works with the road, and if you are, for example, in a park and want to find out how many kilometers you need to walk through desert areas, such a “solution” to the problem will not solve it at all.

However, we would not write the article if we did not have an ace up our sleeve: we're talking about about Maps. The application is updated every day and supplemented with new features; we cannot say exactly when the ability to determine distance appeared, but this is probably one of the most useful functions.

In order to find out the distance traveled or planned path, you need to:

Hold your finger on the starting point, after which additional settings will appear

Swiping up will reveal the settings in full screen

Click on "Measure distance"

Swipe across the display and select a waypoint or destination by tapping on a location on the map

As you progress, the distance shown in the lower left corner will increase. In order to delete the last point, you need to click on the return button, which is located in the upper right corner next to the “Menu” button. By the way, by clicking on three menu points, you can completely clear the entire route.

Thus, we have learned to determine the distance of the route of interest.

It is worth noting the generally stable and high-quality work Google Maps. There are many similar applications in the Play Store, including MAPS.ME, Yandex.Maps, but for some reason it is the solution from Google, firstly, that fits best externally into the system, bringing its own Material features, and secondly, it is software implemented in enough high level. Here you can view the street using a StreetView panorama, download offline navigation, and so on. In a word, if you are interested in maps, feel free to download the official Google solution.

Measuring distances on a map. Study of a site. Reading a map along the route

Studying a site

Based on the relief and local objects depicted on the map, one can judge the suitability of a given area for organizing and conducting combat, for the use of military equipment in combat, for observation conditions, firing, orientation, camouflage, as well as cross-country ability.

Availability on the map large quantity settlements and individual tracts of forest, cliffs and gullies, lakes, rivers and streams indicate rough terrain and limited visibility, which will impede the movement of military and transport equipment off roads and create difficulties in organizing surveillance. At the same time, the rugged nature of the terrain creates good conditions for sheltering and protecting units from the effects of weapons mass destruction enemy, and forest areas can be used to camouflage unit personnel, military equipment, etc.

By the nature of the layout, size and font of the signatures of settlements, we can say that some settlements belong to cities, others to urban-type settlements, and still others to rural-type settlements. The orange coloring of the blocks indicates the predominance of fire-resistant buildings. Black rectangles located close to each other inside the blocks indicate the dense nature of the development, and yellow shading indicates the non-fire resistance of the buildings.

In a populated area there may be a weather station, a power station, a radio mast, a fuel warehouse, a plant with a pipe, a railway station, a flour mill and other objects. Some of these local items can serve as good guidelines.

The map can show a relatively developed network of roads of various classes. If there is a signature on a conventional highway sign, for example, 10 (14) B. This means that the paved part of the road has a width of 10 m, and from ditch to ditch - 14 m, the surface is cobblestone. A single-track (double-track) railway can pass through the area. Studying the route along railway, you can find on the map individual sections of roads that run along an embankment or in a excavation with a specified depth.

With a more detailed study of roads, it is possible to establish: the presence and characteristics of bridges, embankments, excavations and other structures; the presence of difficult areas, steep descents and ascents; possibility of leaving roads and driving near them.

Water surfaces are shown on maps in blue or blue, therefore they clearly stand out among the symbols of other local objects.

By the nature of the font of the river's signature one can judge its navigability. The arrow and number on the river indicate in which direction it flows and at what speed. The signature, for example: means that the width of the river in this place is 250 m, the depth is 4.8 m, and the bottom soil is sandy. If there is a bridge across the river, then next to the image of the bridge its characteristics are given.

If the river on the map is depicted with one line, then this indicates that the width of the river does not exceed 10 m. If the river is depicted in two lines, and its width is not indicated on the map, its width can be determined by the indicated characteristics of the bridges.

If the river is fordable, then the ford symbol indicates the depth of the ford and the soil of the bottom.

When studying the soil and vegetation cover, you can find forest areas of different sizes on the map. Explanatory symbols on the green fill of the forest area may indicate a mixed composition of tree species, deciduous or coniferous forest. A signature, for example: , indicates that average height There are 25 m of trees, their thickness is 30 cm, the average distance between them is 5 m, which allows us to conclude that it is impossible for cars and tanks to move through the forest off-road.

Studying the terrain on a map begins with determining the general nature of the unevenness of the area on which it is to be carried out. combat mission. For example, if the map shows a hilly terrain with relative heights of 100-120 m, and the distance between horizontal lines (laying) is from 10 to 1 mm, this indicates a relatively small steepness of the slopes (from 1 to 10 °).

A detailed study of the terrain on a map is associated with solving problems of determining the heights and mutual elevation of points, the type, direction of steepness of slopes, characteristics (depth, width and length) of hollows, ravines, gullies and other relief details.

Measuring distances on a map

Measuring straight and curved lines using a map

Example, on a map of scale 1:25000 we measure the distance between the bridge and the windmill with a ruler; it is equal to 7.3 cm, multiply 250 m by 7.3 and get the required distance; it is equal to 1825 meters (250x7.3=1825).

Determine the distance between terrain points on the map using a ruler

A small distance between two points in a straight line is easier to determine using a linear scale. To do this, it is enough to apply a measuring compass, the opening of which is equal to the distance between given points on the map, to a linear scale and take a reading in meters or kilometers. In the figure, the measured distance is 1070 m.

Large distances between points along straight lines are usually measured using a long ruler or measuring compass.

In the first case, a numerical scale is used to determine the distance on the map using a ruler.

In the same way, distances are measured along winding lines. In this case, the “step” of the measuring compass should be taken 0.5 or 1 cm, depending on the length and degree of tortuosity of the line being measured.

To determine the length of a route on a map, a special device called a curvimeter is used, which is especially convenient for measuring winding and long lines.

The device has a wheel, which is connected by a gear system to an arrow.

Accuracy of measuring distances on the map. Distance corrections for slope and tortuosity of lines

The accuracy of determining distances on a map depends on the scale of the map, the nature of the measured lines (straight, winding), the chosen measurement method, the terrain and other factors.

The most accurate way to determine the distance on the map is in a straight line.

When measuring distances using a measuring compass or a ruler with millimeter divisions, the average measurement error in flat areas usually does not exceed 0.7-1 mm on the map scale, which is 17.5-25 m for a map at a scale of 1:25000, scale 1:50000 - 35-50 m, scale 1:100000 - 70-100 m.

For example, With a slope steepness of 20° and a distance on the ground of 2120 m, its projection onto the plane (distance on the map) is 2000 m, i.e. 120 m less.

This is explained not only by the presence of ups and downs on the roads, but also by some generalization of road convolutions on maps.

The simplest ways to measure areas on a map

An approximate estimate of the size of the areas is made by eye using the squares of the kilometer grid available on the map. Each grid square of maps of scale 1:10000 - 1:50000 on the ground corresponds to 1 km2, the square of the grid of maps of scale 1:100000 - 4 km2, the square of the grid of maps of scale 1:200000 - 16 km2.

More accurately, areas are measured with a palette, which is a sheet of transparent plastic with a grid of squares with a side of 10 mm applied to it (depending on the scale of the map and the required measurement accuracy).

Using squares of scales 1:25000 and 1:50000, it is convenient to measure the area of small areas with an officer’s ruler, which has special rectangular cutouts. The areas of these rectangles (in hectares) are indicated on the ruler for each gharta scale.

Reading a map along the route

Reading a map means correctly and fully perceiving the symbolism of its conventional signs, quickly and accurately recognizing from them not only the type and varieties of objects depicted, but also their characteristic properties.

Studying a terrain using a map (reading a map) includes determining its general nature, the quantitative and qualitative characteristics of individual elements (local objects and landforms), as well as determining the degree of influence of a given area on the organization and conduct of combat.

When studying the terrain on a map, you should remember that since its creation, changes may have occurred in the area that are not reflected on the map, i.e. the contents of the map will to some extent not correspond to the actual state of the terrain on this moment. Therefore, it is recommended to begin studying the area using a map by familiarizing yourself with the map itself.

Familiarization with the map. When familiarizing yourself with the map, using the information placed in the outer frame, determine the scale, height of the relief section and the time of creation of the map. Data on the scale and height of the relief section will allow you to establish the degree of detail of the image on a given map of local objects, shapes and relief details. Knowing the scale, you can quickly determine the size of local objects or their distance from each other.

Information about the time of creation of the map will make it possible to preliminarily determine the correspondence of the contents of the map to the actual state of the area.

Then they read and, if possible, remember the values of the magnetic needle declination and direction corrections. Knowing the direction correction from memory, you can quickly convert directional angles into magnetic azimuths or orient the map on the ground along the kilometer grid line.

General rules and sequence of studying the area on the map. The sequence and degree of detail in studying the terrain is determined by the specific conditions of the combat situation, the nature of the unit's combat mission, as well as seasonal conditions and tactical and technical data of the military equipment used in carrying out the assigned combat mission. When organizing defense in a city, it is important to determine the nature of its planning and development, identifying durable buildings with basements and underground structures. In the case where the unit’s route passes through the city, there is no need to study the features of the city in such detail. When organizing an offensive in the mountains, the main objects of study are passes, mountain passages, gorges and gorges with adjacent heights, the shape of the slopes and their influence on the organization of the fire system.

The study of terrain, as a rule, begins with determining its general nature, and then studies in detail individual local objects, shapes and details of the relief, their influence on the conditions of observation, camouflage, cross-country ability, protective properties, conditions of fire and orientation.

Determining the general character of the area is aimed at identifying the most important features relief and local objects that have an impact significant influence to complete the assigned task. When determining the general nature of an area based on familiarization with the topography, settlements, roads, hydrographic network and vegetation cover, the variety of the area, the degree of its ruggedness and closedness are identified, which makes it possible to preliminarily determine its tactical and protective properties.

The general character of the area is determined by a quick overview of the entire study area on a map.

At first glance at the map, one can tell that there are settlements and individual tracts of forest, cliffs and gullies, lakes, rivers and streams indicating rough terrain and limited visibility, which inevitably complicates the movement of military and transport equipment off roads and creates difficulties in organizing surveillance . At the same time, the rugged nature of the terrain creates good conditions for sheltering and protecting units from the effects of enemy weapons of mass destruction, and forests can be used to camouflage unit personnel, military equipment, etc.

Thus, as a result of determining the general nature of the terrain, a conclusion is drawn about the accessibility of the area and its individual directions for the operations of units on vehicles, and they also outline boundaries and objects that should be studied in more detail, taking into account the nature of the combat mission to be performed in this area of the terrain.
A detailed study of the area aims to determine the qualitative characteristics of local objects, shapes and relief details within the boundaries of the unit’s operations or along the upcoming route of movement. Based on obtaining such data from a map and taking into account the relationship of topographic elements of the terrain (local objects and relief), an assessment is made of the conditions of cross-country ability, camouflage and surveillance, orientation, firing, and the protective properties of the terrain are determined.

Definition of quality and quantitative characteristics local objects are located on the map with relatively high accuracy and great detail.

When studying settlements using a map, the number of settlements, their type and dispersion are determined, and the degree of habitability of a particular area (district) of the area is determined. The main indicators of the tactical and protective properties of settlements are their area and configuration, the nature of the layout and development, the presence of underground structures, and the nature of the terrain on the approaches to the settlement.

Reading the map conventional signs settlements establish the presence, type and location of them in a given area of the area, determine the nature of the outskirts and layout, building density and fire resistance of buildings, the location of streets, main thoroughfares, the presence of industrial facilities, prominent buildings and landmarks.

When studying a road network map, the degree of development of the road network and the quality of roads are clarified, the passability conditions of a given area and opportunities are determined. effective use Vehicle.

A more detailed study of roads establishes: the presence and characteristics of bridges, embankments, excavations and other structures; the presence of difficult areas, steep descents and ascents; possibility of leaving roads and driving near them.

When exploring dirt roads Special attention pay attention to identifying the carrying capacity of bridges and ferry crossings, since on such roads they are often not designed to accommodate heavy wheeled and tracked vehicles.

By studying hydrography, they determine the presence of water bodies, clarify the degree of ruggedness of the area. Availability water bodies creates good conditions for water supply and transportation along waterways.

Water surfaces are depicted on maps in blue or light blue, so they clearly stand out among the symbols of other local objects. When studying rivers, canals, streams, lakes and other water barriers using a map, the width, depth, flow speed, nature of the bottom soil, banks and surrounding areas are determined; the presence and characteristics of bridges, dams, locks, ferry crossings, fords and areas convenient for crossing are established.

When studying the soil and vegetation cover, the presence and characteristics of forests and shrubs, swamps, salt marshes, sands, rocky placers and those elements of the soil and vegetation cover that can have a significant impact on the conditions of passage, camouflage, observation and the possibility of shelter are determined from the map.

The characteristics of the forest area studied from the map allow us to draw a conclusion about the possibility of using it for a secretive and dispersed location of units, as well as about the passability of the forest along roads and clearings. Good landmarks in the forest for determining your location and orienting yourself while moving are the forester’s house and clearings.

The characteristics of swamps are determined by the outline of symbols. However, when determining the passability of swamps on a map, one should take into account the time of year and weather conditions. During the period of rains and muddy roads, swamps, shown on the map as passable by a symbol, may actually turn out to be difficult to pass. In winter, during severe frosts, impassable swamps can become easily passable.

Studying the terrain on a map begins with determining the general nature of the unevenness of the area of the terrain on which the combat mission is to be carried out. At the same time, the presence, location and mutual relationship of the most typical typical forms and relief details for a given site are established, determined in general view their influence on the conditions of cross-country ability, observation, firing, camouflage, orientation and organization of protection against weapons of mass destruction. The general nature of the relief can be quickly determined by the density and outline of contours, elevation marks and symbols of relief details.

A detailed study of the terrain on a map is associated with solving problems of determining the heights and mutual elevation of points, the type and direction of the steepness of the slopes, the characteristics (depth, width and length) of hollows, ravines, gullies and other relief details.

Naturally, the need to solve specific problems will depend on the nature of the assigned combat mission. For example, the determination of invisibility fields will be required when organizing and conducting surveillance reconnaissance; determining the steepness, height and length of the slopes will be required when determining terrain conditions and choosing a route, etc.

Rice. 20. Measuring distances on a map with a measuring compass

on a linear scale

For example, on a map at a scale of 1:50,000 (scale value 500 m), the distance between two landmarks is 4.2 cm.

Therefore, the required distance between these landmarks on the ground will be equal to 4.2 500 = 2100 m.

A small distance between two points in a straight line is easier to determine using a linear scale (see Fig. 20). To do this, it is enough to apply a measuring compass, the opening of which is equal to the distance between given points on the map, to a linear scale and take a reading in meters or kilometers. In Fig. 20 the measured distance is 1250 m.

Large distances between points along straight lines are usually measured using a long ruler or measuring compass. In the first case, a numerical scale is used to determine the distance on the map using a ruler. In the second case, the opening (“step”) of the measuring compass is set so that it corresponds to an integer number of kilometers, and an integer number of “steps” are plotted on the segment measured on the map. The distance that does not fit into the whole number of “steps” of the measuring compass is determined using a linear scale and added to the resulting number of kilometers.

In this way, distances are measured along winding lines. In this case, the “step” of the measuring compass should be 0.5 or 1 cm, depending on the length and degree of tortuosity of the line being measured (Fig. 21).

Rice. 21. Measuring distances along curved lines

To determine the length of a route on a map, a special device called a curvimeter is used. It is convenient for measuring curved and long lines. The device has a wheel, which is connected by a gear system to an arrow. When measuring distance with a curvimeter, you need to set its needle to the zero division, and then roll the wheel along the route so that the scale readings increase. The resulting reading in centimeters is multiplied by the scale value and the distance on the ground is obtained.

The accuracy of determining distances on a map depends on the scale of the map, the nature of the measured lines (straight, winding), the chosen method of measuring the terrain and other factors.

The most accurate way to determine the distance on the map is in a straight line. When measuring distances using a measuring compass or a ruler with millimeter divisions, the average measurement error on flat areas of the terrain usually does not exceed 0.5–1 mm on the map scale, which is 12.5–25 m for a map of scale 1: 25,000 , scale 1: 50,000 – 25–50 m, scale 1: 100,000 – 50–100 m. In mountainous areas with steep slopes, errors will be greater. This is explained by the fact that when surveying a terrain, it is not the length of the lines on the Earth’s surface that is plotted on the map, but the length of the projections of these lines onto the plane.

With a slope steepness of 20° and a distance on the ground of 2120 m, its projection onto the plane (distance on the map) is 2000 m, i.e. 120 m less. It is calculated that with an inclination angle (steepness of the slope) of 20°, the resulting distance measurement result on the map should be increased by 6% (add 6 m per 100 m), with an inclination angle of 30° - by 15%, and with an angle of 40° - by 23 %.

When determining the length of a route on a map, it should be taken into account that road distances measured on the map using a compass or curvimeter are shorter than the actual distances. This is explained not only by the presence of ups and downs on the roads, but also by some generalization of road convolutions on maps. Therefore, the result of measuring the length of the route obtained from the map should, taking into account the nature of the terrain and the scale of the map, be multiplied by the coefficient indicated in the table. 3.