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Lesson questions:
1. Coordinate systems used in topography: geographic, flat rectangular, polar and bipolar coordinates, their essence and use.
Coordinates are called angular and linear quantities (numbers) that determine the position of a point on any surface or in space.
In topography, coordinate systems are used that make it possible to most simply and unambiguously determine the position of points earth's surface both from the results of direct measurements on the ground and using maps. Such systems include geographic, flat rectangular, polar and bipolar coordinates.
Geographical coordinates(Fig. 1) – angular values: latitude (j) and longitude (L), which determine the position of an object on the earth’s surface relative to the origin of coordinates – the point of intersection of the prime (Greenwich) meridian with the equator. On a map, the geographic grid is indicated by a scale on all sides of the map frame. The western and eastern sides of the frame are meridians, and the northern and southern sides are parallels. In the corners of the map sheet, the geographical coordinates of the intersection points of the sides of the frame are written.
Rice. 1. System geographical coordinates on the earth's surface |
In the geographic coordinate system, the position of any point on the earth's surface relative to the origin of coordinates is determined in angular measure. In our country and in most other countries, the point of intersection of the prime (Greenwich) meridian with the equator is taken as the beginning. Being thus uniform for our entire planet, the system of geographic coordinates is convenient for solving problems of determining the relative position of objects located at significant distances from each other. Therefore, in military affairs, this system is used mainly for conducting calculations related to the use of long-range combat weapons, for example, ballistic missiles, aviation, etc.
Plane rectangular coordinates(Fig. 2) - linear quantities that determine the position of an object on a plane relative to the accepted origin of coordinates - the intersection of two mutually perpendicular lines (coordinate axes X and Y).
In topography, each 6-degree zone has its own system of rectangular coordinates. The X axis is the axial meridian of the zone, the Y axis is the equator, and the point of intersection of the axial meridian with the equator is the origin of coordinates.
The plane rectangular coordinate system is zonal; it is established for each six-degree zone into which the Earth’s surface is divided when depicting it on maps in the Gaussian projection, and is intended to indicate the position of images of points of the earth’s surface on a plane (map) in this projection.
The origin of coordinates in a zone is the point of intersection of the axial meridian with the equator, relative to which the position of all other points in the zone is determined in a linear measure. The origin of the zone and its coordinate axes occupy a strictly defined position on the earth's surface. Therefore, the system of flat rectangular coordinates of each zone is connected both with the coordinate systems of all other zones, and with the system of geographical coordinates.
The use of linear quantities to determine the position of points makes the system of flat rectangular coordinates very convenient for carrying out calculations both when working on the ground and on a map. Therefore, this system is most widely used among the troops. Rectangular coordinates indicate the position of terrain points, their battle formations and targets, and with their help determine the relative position of objects within one coordinate zone or in adjacent areas of two zones.
Polar and bipolar coordinate systems are local systems. In military practice, they are used to determine the position of some points relative to others in relatively small areas of the terrain, for example, when designating targets, marking landmarks and targets, drawing up terrain diagrams, etc. These systems can be associated with systems of rectangular and geographic coordinates.
2. Determining geographic coordinates and plotting objects on a map using known coordinates.
The geographic coordinates of a point located on the map are determined from the nearest parallel and meridian, the latitude and longitude of which are known.
Frame topographic map divided into minutes, which are separated by dots into divisions of 10 seconds each. Latitudes are indicated on the sides of the frame, and longitudes are indicated on the northern and southern sides.
Using the minute frame of the map you can:
1
. Determine the geographic coordinates of any point on the map.
For example, the coordinates of point A (Fig. 3). To do this, you need to use a measuring compass to measure the shortest distance from point A to the southern frame of the map, then attach the meter to the western frame and determine the number of minutes and seconds in the measured segment, add the resulting (measured) value of minutes and seconds (0"27") with the latitude of the southwest corner of the frame - 54°30".
Latitude points on the map will be equal to: 54°30"+0"27" = 54°30"27".
Longitude is defined similarly.
Using a measuring compass, measure the shortest distance from point A to the western frame of the map, apply the measuring compass to the southern frame, determine the number of minutes and seconds in the measured segment (2"35"), add the resulting (measured) value to the longitude of the southwestern corner frames - 45°00".
Longitude points on the map will be equal to: 45°00"+2"35" = 45°02"35"
2. Plot any point on the map according to the given geographical coordinates.
For example, point B latitude: 54°31 "08", longitude 45°01 "41".
To plot a point in longitude on a map, it is necessary to draw the true meridian through this point, for which you connect the same number of minutes along the northern and southern frames; To plot a point in latitude on a map, it is necessary to draw a parallel through this point, for which you connect the same number of minutes along the western and eastern frames. The intersection of two lines will determine the location of point B.
3. Rectangular coordinate grid on topographic maps and its digitization. Additional grid at the junction of coordinate zones.
The coordinate grid on the map is a grid of squares formed by lines parallel to the coordinate axes of the zone. Grid lines are drawn through an integer number of kilometers. Therefore, the coordinate grid is also called the kilometer grid, and its lines are kilometer.
On a 1:25000 map, the lines forming the coordinate grid are drawn through 4 cm, that is, through 1 km on the ground, and on maps 1:50000-1:200000 through 2 cm (1.2 and 4 km on the ground, respectively). On a 1:500000 map, only the outputs of the coordinate grid lines are plotted on the inner frame of each sheet every 2 cm (10 km on the ground). If necessary, coordinate lines can be drawn on the map along these outputs.
On topographic maps, the values of the abscissa and ordinate of coordinate lines (Fig. 2) are signed at the exits of the lines outside the inner frame of the sheet and in nine places on each sheet of the map. Full values The abscissa and ordinate in kilometers are signed near the coordinate lines closest to the corners of the map frame and near the intersection of the coordinate lines closest to the northwestern corner. The remaining coordinate lines are abbreviated with two numbers (tens and units of kilometers). The labels near the horizontal grid lines correspond to the distances from the ordinate axis in kilometers.
Labels near the vertical lines indicate the zone number (one or two first digits) and the distance in kilometers (always three digits) from the origin of coordinates, conventionally moved west of the zone’s axial meridian by 500 km. For example, the signature 6740 means: 6 - zone number, 740 - distance from the conventional origin in kilometers.
On the outer frame there are outputs of coordinate lines ( additional mesh) coordinate system of the adjacent zone.
4. Determination of rectangular coordinates of points. Drawing points on a map according to their coordinates.
Using a coordinate grid using a compass (ruler), you can:
1.
Determine the rectangular coordinates of a point on the map.
For example, points B (Fig. 2).
To do this you need:
- write X - digitization of the bottom kilometer line of the square in which point B is located, i.e. 6657 km;
- measure the perpendicular distance from the bottom kilometer line of the square to point B and, using the linear scale of the map, determine the size of this segment in meters;
- add the measured value of 575 m with the digitization value of the lower kilometer line of the square: X=6657000+575=6657575 m.
The Y ordinate is determined in the same way:
- write down the Y value - digitization of the left vertical line of the square, i.e. 7363;
- measure the perpendicular distance from this line to point B, i.e. 335 m;
- add the measured distance to the Y digitization value of the left vertical line of the square: Y=7363000+335=7363335 m.
2.
Place the target on the map at the given coordinates.
For example, point G at coordinates: X=6658725 Y=7362360.
To do this you need:
- find the square in which point G is located according to the value of whole kilometers, i.e. 5862;
- set aside from the lower left corner of the square a segment on the map scale equal to the difference between the abscissa of the target and the bottom side of the square - 725 m;
- - from the obtained point, along the perpendicular to the right, plot a segment equal to the difference between the ordinates of the target and the left side of the square, i.e. 360 m.
The accuracy of determining geographic coordinates using 1:25000-1:200000 maps is about 2 and 10"" respectively.
The accuracy of determining the rectangular coordinates of points from a map is limited not only by its scale, but also by the magnitude of errors allowed when shooting or drawing up a map and drawing it on it. various points and terrain objects
Most accurately (with an error not exceeding 0.2 mm) geodetic points and are plotted on the map. objects that stand out most sharply in the area and are visible from a distance, having the significance of landmarks (individual bell towers, factory chimneys, tower-type buildings). Therefore, the coordinates of such points can be determined with approximately the same accuracy with which they are plotted on the map, i.e. for a map of scale 1:25000 - with an accuracy of 5-7 m, for a map of scale 1:50000 - with an accuracy of 10-15 m, for a map of scale 1:100000 - with an accuracy of 20-30 m.
The remaining landmarks and contour points are plotted on the map, and, therefore, determined from it with an error of up to 0.5 mm, and points related to contours that are not clearly defined on the ground (for example, the contour of a swamp), with an error of up to 1 mm.
6. Determining the position of objects (points) in polar and bipolar coordinate systems, plotting objects on a map by direction and distance, by two angles or by two distances.
System flat polar coordinates(Fig. 3, a) consists of point O - the origin, or poles, and the initial direction of the OR, called polar axis.
System flat bipolar (two-pole) coordinates(Fig. 3, b) consists of two poles A and B and a common axis AB, called the basis or base of the notch. The position of any point M relative to two data on the map (terrain) of points A and B is determined by the coordinates that are measured on the map or on the terrain.
These coordinates can be either two position angles that determine the directions from points A and B to the desired point M, or the distances D1=AM and D2=BM to it. The position angles in this case, as shown in Fig. 1, b, are measured at points A and B or from the direction of the basis (i.e. angle A = BAM and angle B = ABM) or from any other directions passing through points A and B and taken as the initial ones. For example, in the second case, the location of point M is determined by the position angles θ1 and θ2, measured from the direction of the magnetic meridians.
Drawing a detected object on a map
This is one of the most important moments in object detection. The accuracy of determining its coordinates depends on how accurately the object (target) is plotted on the map.
Having detected an object (target), you must first accurately determine various signs what is discovered. Then, without stopping observing the object and without detecting yourself, put the object on the map. There are several ways to plot an object on a map.
Visually: A feature is plotted on the map if it is near a known landmark.
By direction and distance: to do this, you need to orient the map, find the point of your standing on it, indicate on the map the direction to the detected object and draw a line to the object from the point of your standing, then determine the distance to the object by measuring this distance on the map and comparing it with the scale of the map.
 Rice. 4. Drawing the target on the map using a straight line |
If it is graphically impossible to solve the problem in this way (the enemy is in the way, poor visibility, etc.), then you need to accurately measure the azimuth to the object, then translate it into a directional angle and draw on the map from the standing point the direction at which to plot the distance to the object. |
7. Methods of target designation on the map: in graphic coordinates, flat rectangular coordinates (full and abbreviated), by kilometer grid squares (up to a whole square, up to 1/4, up to 1/9 square), from a landmark, from a conventional line, in azimuth and target range, in a bipolar coordinate system.
The ability to quickly and correctly indicate targets, landmarks and other objects on the ground is important for controlling units and fire in battle or for organizing battle.
Targeting in geographical coordinates used very rarely and only in cases where targets are located at a considerable distance from a given point on the map, expressed in tens or hundreds of kilometers. In this case, geographic coordinates are determined from the map, as described in question No. 2 of this lesson.
The location of the target (object) is indicated by latitude and longitude, for example, height 245.2 (40° 8" 40" N, 65° 31" 00" E). On the eastern (western), northern (southern) sides of the topographic frame, marks of the target position in latitude and longitude are applied with a compass. From these marks, perpendiculars are lowered into the depth of the topographic map sheet until they intersect (commander’s rulers and standard sheets of paper are applied). The point of intersection of the perpendiculars is the position of the target on the map.
For approximate target designation by rectangular coordinates It is enough to indicate on the map the grid square in which the object is located. The square is always indicated by the numbers of the kilometer lines, the intersection of which forms the southwest (lower left) corner. When indicating the square of the map, the following rule is followed: first they call two numbers signed at the horizontal line (on the western side), that is, the “X” coordinate, and then two numbers at the vertical line (the southern side of the sheet), that is, the “Y” coordinate. In this case, “X” and “Y” are not said. For example, enemy tanks were detected. When transmitting a report by radiotelephone, the square number is pronounced: "eighty eight zero two."
If the position of a point (object) needs to be determined more accurately, then full or abbreviated coordinates are used.
Work with full coordinates. For example, you need to determine the coordinates of a road sign in square 8803 on a map at a scale of 1:50000. First, determine the distance from the bottom horizontal side of the square to the road sign (for example, 600 m on the ground). In the same way, measure the distance from the left vertical side of the square (for example, 500 m). Now, by digitizing kilometer lines, we determine the full coordinates of the object. The horizontal line has the signature 5988 (X), adding the distance from this line to the road sign, we get: X = 5988600. We define the vertical line in the same way and get 2403500. The full coordinates of the road sign are as follows: X=5988600 m, Y=2403500 m.
Abbreviated coordinates respectively will be equal: X=88600 m, Y=03500 m.
If it is necessary to clarify the position of a target in a square, then target designation is used in an alphabetic or digital way inside the square of a kilometer grid.
During target designation literal way inside the square of the kilometer grid, the square is conditionally divided into 4 parts, each part is assigned a capital letter of the Russian alphabet.
Second way - digital way target designation inside the square kilometer grid (target designation by snail
). This method got its name from the arrangement of conventional digital squares inside the square of the kilometer grid. They are arranged as if in a spiral, with the square divided into 9 parts.
When designating targets in these cases, they name the square in which the target is located, and add a letter or number that specifies the position of the target inside the square. For example, height 51.8 (5863-A) or high-voltage support (5762-2) (see Fig. 2).
Target designation from a landmark is the simplest and most common method of target designation. With this method of target designation, the landmark closest to the target is first named, then the angle between the direction to the landmark and the direction to the target in protractor divisions (measured with binoculars) and the distance to the target in meters. For example: “Landmark two, forty to the right, further two hundred, near a separate bush there is a machine gun.”
Target designation from the conditional line usually used in motion on combat vehicles. With this method, two points are selected on the map in the direction of action and connected by a straight line, relative to which target designation will be carried out. This line is denoted by letters, divided into centimeter divisions and numbered starting from zero. This construction is done on the maps of both transmitting and receiving target designation.
Target designation from a conventional line is usually used in movement on combat vehicles. With this method, two points are selected on the map in the direction of action and connected by a straight line (Fig. 5), relative to which target designation will be carried out. This line is denoted by letters, divided into centimeter divisions and numbered starting from zero.
 Rice. 5. Target designation from the conditional line |
This construction is done on the maps of both transmitting and receiving target designation. |
Target designation from a conventional line can be given by indicating the direction to the target at an angle from the conventional line and the distance to the target, for example: “Straight AC, right 3-40, one thousand two hundred – machine gun.”
Target designation in azimuth and range to the target. The azimuth of the direction to the target is determined using a compass in degrees, and the distance to it is determined using an observation device or by eye in meters. For example: “Azimuth thirty-five, range six hundred—a tank in a trench.”
This method is most often used in areas where there are few landmarks.
8. Problem solving.
Determining the coordinates of terrain points (objects) and target designation on the map is practiced practically on training maps using previously prepared points (marked objects).
Each student determines geographic and rectangular coordinates (maps objects according to known coordinates).
Methods of target designation on the map are worked out: in flat rectangular coordinates (full and abbreviated), by squares of a kilometer grid (up to a whole square, up to 1/4, up to 1/9 of a square), from a landmark, along the azimuth and range of the target.
Notes
Military topography
Military ecology
Military medical training
Engineering training
Fire training
It is possible to determine the location of a point on planet Earth, as on any other spherical planet, using geographic coordinates - latitude and longitude. The intersections of circles and arcs at right angles create a corresponding grid, which allows you to unambiguously determine the coordinates. A good example is an ordinary school globe, lined with horizontal circles and vertical arcs. How to use the globe will be discussed below.
This system is measured in degrees (degree of angle). The angle is calculated strictly from the center of the sphere to a point on the surface. Relative to the axis, the degree of latitude angle is calculated vertically, longitude - horizontally. To calculate exact coordinates, there are special formulas, where another quantity is often found - height, which serves mainly to represent three-dimensional space and allows calculations to be made to determine the position of a point relative to sea level.
Latitude and longitude - terms and definitions
The earth's sphere is divided by an imaginary horizontal line into two equal parts of the world - the northern and southern hemispheres - into positive and negative poles, respectively. This is how the definitions of northern and southern latitudes were introduced. Latitude is represented as circles parallel to the equator, called parallels. The equator itself, with a value of 0 degrees, acts as the starting point for measurements. The closer the parallel is to the upper or lower pole, the smaller its diameter and the higher or lower the angular degree. For example, the city of Moscow is located at 55 degrees north latitude, which determines the location of the capital as approximately equidistant from both the equator and the north pole.
Meridian is the name of longitude, represented as a vertical arc strictly perpendicular to the circles of parallel. The sphere is divided into 360 meridians. The reference point is the prime meridian (0 degrees), the arcs of which pass vertically through the points of the north and south poles and extend to the east and western directions. This determines the angle of longitude from 0 to 180 degrees, calculated from the center to the extreme points to the east or south.
Unlike latitude, the reference point of which is the equatorial line, any meridian can be the zero meridian. But for convenience, namely the convenience of counting time, the Greenwich meridian was determined.
Geographic coordinates – place and time
Latitude and longitude allow you to assign a precise geographic address, measured in degrees, to a particular place on the planet. Degrees, in turn, are divided into smaller units such as minutes and seconds. Each degree is divided into 60 parts (minutes), and a minute into 60 seconds. Using Moscow as an example, the entry looks like this: 55° 45′ 7″ N, 37° 36′ 56″ E or 55 degrees, 45 minutes, 7 seconds north latitude and 37 degrees, 36 minutes, 56 seconds south longitude.
The interval between the meridians is 15 degrees and about 111 km along the equator - this is the distance the Earth, rotating, travels in one hour. It takes 24 hours to complete a full rotation of a day.
We use the globe
The model of the Earth is accurately depicted on the globe with realistic depictions of all continents, seas and oceans. Parallels and meridians are drawn on the globe map as auxiliary lines. Almost any globe has a crescent-shaped meridian in its design, which is installed on the base and serves as an auxiliary measure.
The meridian arc is equipped with a special degree scale by which latitude is determined. Longitude can be found out using another scale - a hoop mounted horizontally at the equator. By marking the desired location with your finger and rotating the globe around its axis to the auxiliary arc, we fix the latitude value (depending on the location of the object, it will be either north or south). Then we mark the data on the equator scale at the point of its intersection with the meridian arc and determine the longitude. You can find out whether it is eastern or southern longitude only relative to the prime meridian.
Coordinates are called angular and linear quantities (numbers) that determine the position of a point on any surface or in space.
In topography, coordinate systems are used that make it possible to most simply and unambiguously determine the position of points on the earth's surface, both from the results of direct measurements on the ground and using maps. Such systems include geographic, flat rectangular, polar and bipolar coordinates.
Geographical coordinates(Fig. 1) – angular values: latitude (j) and longitude (L), which determine the position of an object on the earth’s surface relative to the origin of coordinates – the point of intersection of the prime (Greenwich) meridian with the equator. On a map, the geographic grid is indicated by a scale on all sides of the map frame. The western and eastern sides of the frame are meridians, and the northern and southern sides are parallels. In the corners of the map sheet, the geographical coordinates of the intersection points of the sides of the frame are written.
Rice. 1. System of geographical coordinates on the earth's surface
In the geographic coordinate system, the position of any point on the earth's surface relative to the origin of coordinates is determined in angular measure. In our country and in most other countries, the point of intersection of the prime (Greenwich) meridian with the equator is taken as the beginning. Being thus uniform for our entire planet, the system of geographic coordinates is convenient for solving problems of determining the relative position of objects located at significant distances from each other. Therefore, in military affairs, this system is used mainly for conducting calculations related to the use of long-range combat weapons, for example, ballistic missiles, aviation, etc.
Plane rectangular coordinates(Fig. 2) - linear quantities that determine the position of an object on a plane relative to the accepted origin of coordinates - the intersection of two mutually perpendicular lines (coordinate axes X and Y).
In topography, each 6-degree zone has its own system of rectangular coordinates. The X axis is the axial meridian of the zone, the Y axis is the equator, and the point of intersection of the axial meridian with the equator is the origin of coordinates.
Rice. 2. System of flat rectangular coordinates on maps
The plane rectangular coordinate system is zonal; it is established for each six-degree zone into which the Earth’s surface is divided when depicting it on maps in the Gaussian projection, and is intended to indicate the position of images of points of the earth’s surface on a plane (map) in this projection.
The origin of coordinates in a zone is the point of intersection of the axial meridian with the equator, relative to which the position of all other points in the zone is determined in a linear measure. The origin of the zone and its coordinate axes occupy a strictly defined position on the earth's surface. Therefore, the system of flat rectangular coordinates of each zone is connected both with the coordinate systems of all other zones, and with the system of geographical coordinates.
The use of linear quantities to determine the position of points makes the system of flat rectangular coordinates very convenient for carrying out calculations both when working on the ground and on a map. Therefore, this system is most widely used among the troops. Rectangular coordinates indicate the position of terrain points, their battle formations and targets, and with their help determine the relative position of objects within one coordinate zone or in adjacent areas of two zones.
Polar and bipolar coordinate systems are local systems. In military practice, they are used to determine the position of some points relative to others in relatively small areas of the terrain, for example, when designating targets, marking landmarks and targets, drawing up terrain diagrams, etc. These systems can be associated with systems of rectangular and geographic coordinates.
2. Determining geographic coordinates and plotting objects on a map using known coordinates
The geographic coordinates of a point located on the map are determined from the nearest parallel and meridian, the latitude and longitude of which are known.
The topographic map frame is divided into minutes, which are separated by dots into divisions of 10 seconds each. Latitudes are indicated on the sides of the frame, and longitudes are indicated on the northern and southern sides.
Rice. 3. Determining the geographic coordinates of a point on the map (point A) and plotting the point on the map according to geographic coordinates (point B)
Using the minute frame of the map you can:
1 . Determine the geographic coordinates of any point on the map.
For example, the coordinates of point A (Fig. 3). To do this, you need to use a measuring compass to measure the shortest distance from point A to the southern frame of the map, then attach the meter to the western frame and determine the number of minutes and seconds in the measured segment, add the resulting (measured) value of minutes and seconds (0"27") with the latitude of the southwest corner of the frame - 54°30".
Latitude points on the map will be equal to: 54°30"+0"27" = 54°30"27".
Longitude is defined similarly.
Using a measuring compass, measure the shortest distance from point A to the western frame of the map, apply the measuring compass to the southern frame, determine the number of minutes and seconds in the measured segment (2"35"), add the resulting (measured) value to the longitude of the southwestern corner frames - 45°00".
Longitude points on the map will be equal to: 45°00"+2"35" = 45°02"35"
2. Plot any point on the map according to the given geographical coordinates.
For example, point B latitude: 54°31 "08", longitude 45°01 "41".
To plot a point in longitude on a map, it is necessary to draw the true meridian through this point, for which you connect the same number of minutes along the northern and southern frames; To plot a point in latitude on a map, it is necessary to draw a parallel through this point, for which you connect the same number of minutes along the western and eastern frames. The intersection of two lines will determine the location of point B.
3. Rectangular coordinate grid on topographic maps and its digitization. Additional grid at the junction of coordinate zones
The coordinate grid on the map is a grid of squares formed by lines parallel to the coordinate axes of the zone. Grid lines are drawn through an integer number of kilometers. Therefore, the coordinate grid is also called the kilometer grid, and its lines are kilometer.
On a 1:25000 map, the lines forming the coordinate grid are drawn through 4 cm, that is, through 1 km on the ground, and on maps 1:50000-1:200000 through 2 cm (1.2 and 4 km on the ground, respectively). On a 1:500000 map, only the outputs of the coordinate grid lines are plotted on the inner frame of each sheet every 2 cm (10 km on the ground). If necessary, coordinate lines can be drawn on the map along these outputs.
On topographic maps, the values of the abscissa and ordinate of coordinate lines (Fig. 2) are signed at the exits of the lines outside the inner frame of the sheet and in nine places on each sheet of the map. The full values of the abscissa and ordinate in kilometers are written near the coordinate lines closest to the corners of the map frame and near the intersection of the coordinate lines closest to the northwestern corner. The remaining coordinate lines are abbreviated with two numbers (tens and units of kilometers). The labels near the horizontal grid lines correspond to the distances from the ordinate axis in kilometers.
Labels near the vertical lines indicate the zone number (one or two first digits) and the distance in kilometers (always three digits) from the origin of coordinates, conventionally moved west of the zone’s axial meridian by 500 km. For example, the signature 6740 means: 6 - zone number, 740 - distance from the conventional origin in kilometers.
On the outer frame there are outputs of coordinate lines ( additional mesh) coordinate system of the adjacent zone.
4. Determination of rectangular coordinates of points. Drawing points on a map by their coordinates
Using a coordinate grid using a compass (ruler), you can:
1. Determine the rectangular coordinates of a point on the map.
For example, points B (Fig. 2).
To do this you need:
- write down X - digitization of the bottom kilometer line of the square in which point B is located, i.e. 6657 km;
- measure the perpendicular distance from the bottom kilometer line of the square to point B and, using the linear scale of the map, determine the size of this segment in meters;
- add the measured value of 575 m with the digitization value of the lower kilometer line of the square: X=6657000+575=6657575 m.
The Y ordinate is determined in the same way:
- write down the Y value - digitization of the left vertical line of the square, i.e. 7363;
- measure the perpendicular distance from this line to point B, i.e. 335 m;
- add the measured distance to the Y digitization value of the left vertical line of the square: Y=7363000+335=7363335 m.
2. Place the target on the map at the given coordinates.
For example, point G at coordinates: X=6658725 Y=7362360.
To do this you need:
- find the square in which point G is located according to the value of whole kilometers, i.e. 5862;
- set aside from the lower left corner of the square a segment on the map scale equal to the difference between the abscissa of the target and the bottom side of the square - 725 m;
- From the obtained point, along the perpendicular to the right, plot a segment equal to the difference between the ordinates of the target and the left side of the square, i.e. 360 m.
Rice. 2. Determining the rectangular coordinates of a point on the map (point B) and plotting the point on the map using rectangular coordinates (point D)
5. Accuracy of determining coordinates on maps of various scales
The accuracy of determining geographic coordinates using 1:25000-1:200000 maps is about 2 and 10"" respectively.
The accuracy of determining the rectangular coordinates of points from a map is limited not only by its scale, but also by the magnitude of errors allowed when shooting or drawing up a map and plotting various points and terrain objects on it
Most accurately (with an error not exceeding 0.2 mm) geodetic points and are plotted on the map. objects that stand out most sharply in the area and are visible from a distance, having the significance of landmarks (individual bell towers, factory chimneys, tower-type buildings). Therefore, the coordinates of such points can be determined with approximately the same accuracy with which they are plotted on the map, i.e. for a map of scale 1:25000 - with an accuracy of 5-7 m, for a map of scale 1:50000 - with an accuracy of 10- 15 m, for a map of scale 1:100000 - with an accuracy of 20-30 m.
The remaining landmarks and contour points are plotted on the map, and, therefore, determined from it with an error of up to 0.5 mm, and points related to contours that are not clearly defined on the ground (for example, the contour of a swamp), with an error of up to 1 mm.
6. Determining the position of objects (points) in polar and bipolar coordinate systems, plotting objects on a map by direction and distance, by two angles or by two distances
System flat polar coordinates(Fig. 3, a) consists of point O - the origin, or poles, and the initial direction of the OR, called polar axis.
Rice. 3. a – polar coordinates; b – bipolar coordinates
The position of point M on the ground or on the map in this system is determined by two coordinates: the position angle θ, which is measured clockwise from the polar axis to the direction to the determined point M (from 0 to 360°), and the distance OM=D.
Depending on the problem being solved, the pole is taken to be an observation point, firing position, starting point of movement, etc., and the polar axis is the geographic (true) meridian, magnetic meridian (direction of the magnetic compass needle), or the direction to some landmark .
These coordinates can be either two position angles that determine the directions from points A and B to the desired point M, or the distances D1=AM and D2=BM to it. The position angles in this case, as shown in Fig. 1, b, are measured at points A and B or from the direction of the basis (i.e. angle A = BAM and angle B = ABM) or from any other directions passing through points A and B and taken as the initial ones. For example, in the second case, the location of point M is determined by the position angles θ1 and θ2, measured from the direction of the magnetic meridians. System flat bipolar (two-pole) coordinates(Fig. 3, b) consists of two poles A and B and a common axis AB, called the basis or base of the notch. The position of any point M relative to two data on the map (terrain) of points A and B is determined by the coordinates that are measured on the map or on the terrain.
Drawing a detected object on a map
This is one of the most important points in detecting an object. The accuracy of determining its coordinates depends on how accurately the object (target) is plotted on the map.
Having discovered an object (target), you must first accurately determine by various signs what has been detected. Then, without stopping observing the object and without detecting yourself, put the object on the map. There are several ways to plot an object on a map.
Visually: A feature is plotted on the map if it is near a known landmark.
By direction and distance: to do this, you need to orient the map, find the point of your standing on it, indicate on the map the direction to the detected object and draw a line to the object from the point of your standing, then determine the distance to the object by measuring this distance on the map and comparing it with the scale of the map.
Rice. 4. Drawing the target on the map with a straight line from two points.
If it is graphically impossible to solve the problem in this way (the enemy is in the way, poor visibility, etc.), then you need to accurately measure the azimuth to the object, then translate it into a directional angle and draw on the map from the standing point the direction at which to plot the distance to the object.
To obtain a directional angle, you need to add the magnetic declination of a given map to the magnetic azimuth (direction correction).
Straight serif. In this way, an object is placed on a map of 2-3 points from which it can be observed. To do this, from each selected point, the direction to the object is drawn on an oriented map, then the intersection of straight lines determines the location of the object.
7. Methods of target designation on the map: in graphic coordinates, flat rectangular coordinates (full and abbreviated), by kilometer grid squares (up to a whole square, up to 1/4, up to 1/9 square), from a landmark, from a conventional line, in azimuth and target range, in the bipolar coordinate system
The ability to quickly and correctly indicate targets, landmarks and other objects on the ground is important for controlling units and fire in battle or for organizing battle.
Targeting in geographical coordinates used very rarely and only in cases where targets are located at a considerable distance from a given point on the map, expressed in tens or hundreds of kilometers. In this case, geographic coordinates are determined from the map, as described in question No. 2 of this lesson.
The location of the target (object) is indicated by latitude and longitude, for example, height 245.2 (40° 8" 40" N, 65° 31" 00" E). On the eastern (western), northern (southern) sides of the topographic frame, marks of the target position in latitude and longitude are applied with a compass. From these marks, perpendiculars are lowered into the depth of the topographic map sheet until they intersect (commander’s rulers and standard sheets of paper are applied). The point of intersection of the perpendiculars is the position of the target on the map.
For approximate target designation by rectangular coordinates It is enough to indicate on the map the grid square in which the object is located. The square is always indicated by the numbers of the kilometer lines, the intersection of which forms the southwest (lower left) corner. When indicating the square of the map, the following rule is followed: first they call two numbers signed at the horizontal line (on the western side), that is, the “X” coordinate, and then two numbers at the vertical line (the southern side of the sheet), that is, the “Y” coordinate. In this case, “X” and “Y” are not said. For example, enemy tanks were detected. When transmitting a report by radiotelephone, the square number is pronounced: "eighty eight zero two."
If the position of a point (object) needs to be determined more accurately, then full or abbreviated coordinates are used.
Work with full coordinates. For example, you need to determine the coordinates of a road sign in square 8803 on a map at a scale of 1:50000. First, determine the distance from the bottom horizontal side of the square to the road sign (for example, 600 m on the ground). In the same way, measure the distance from the left vertical side of the square (for example, 500 m). Now, by digitizing kilometer lines, we determine the full coordinates of the object. The horizontal line has the signature 5988 (X), adding the distance from this line to the road sign, we get: X = 5988600. We define the vertical line in the same way and get 2403500. The full coordinates of the road sign are as follows: X=5988600 m, Y=2403500 m.
Abbreviated coordinates respectively will be equal: X=88600 m, Y=03500 m.
If it is necessary to clarify the position of a target in a square, then target designation is used in an alphabetic or digital way inside the square of a kilometer grid.
During target designation literal way inside the square of the kilometer grid, the square is conditionally divided into 4 parts, each part is assigned a capital letter of the Russian alphabet.
Second way - digital way target designation inside the square kilometer grid (target designation by snail ). This method got its name from the arrangement of conventional digital squares inside the square of the kilometer grid. They are arranged as if in a spiral, with the square divided into 9 parts.
When designating targets in these cases, they name the square in which the target is located, and add a letter or number that specifies the position of the target inside the square. For example, height 51.8 (5863-A) or high-voltage support (5762-2) (see Fig. 2).
Target designation from a landmark is the simplest and most common method of target designation. With this method of target designation, the landmark closest to the target is first named, then the angle between the direction to the landmark and the direction to the target in protractor divisions (measured with binoculars) and the distance to the target in meters. For example: “Landmark two, forty to the right, further two hundred, near a separate bush there is a machine gun.”
Target designation from the conditional line usually used in motion on combat vehicles. With this method, two points are selected on the map in the direction of action and connected by a straight line, relative to which target designation will be carried out. This line is denoted by letters, divided into centimeter divisions and numbered starting from zero. This construction is done on the maps of both transmitting and receiving target designation.
Target designation from a conventional line is usually used in movement on combat vehicles. With this method, two points are selected on the map in the direction of action and connected by a straight line (Fig. 5), relative to which target designation will be carried out. This line is denoted by letters, divided into centimeter divisions and numbered starting from zero.
Rice. 5. Target designation from the conditional line
This construction is done on the maps of both transmitting and receiving target designation.
The position of the target relative to the conditional line is determined by two coordinates: a segment from the starting point to the base of the perpendicular lowered from the target location point to the conditional line, and a perpendicular segment from the conditional line to the target.
When designating targets, the conventional name of the line is called, then the number of centimeters and millimeters contained in the first segment, and, finally, the direction (left or right) and the length of the second segment. For example: “Straight AC, five, seven; to the right zero, six - NP.”
Target designation from a conventional line can be given by indicating the direction to the target at an angle from the conventional line and the distance to the target, for example: “Straight AC, right 3-40, one thousand two hundred – machine gun.”
Target designation in azimuth and range to the target. The azimuth of the direction to the target is determined using a compass in degrees, and the distance to it is determined using an observation device or by eye in meters. For example: “Azimuth thirty-five, range six hundred—a tank in a trench.” This method is most often used in areas where there are few landmarks.
8. Problem solving
Determining the coordinates of terrain points (objects) and target designation on the map is practiced practically on training maps using previously prepared points (marked objects).
Each student determines geographic and rectangular coordinates (maps objects according to known coordinates).
Methods of target designation on the map are worked out: in flat rectangular coordinates (full and abbreviated), by squares of a kilometer grid (up to a whole square, up to 1/4, up to 1/9 of a square), from a landmark, along the azimuth and range of the target.
Modern technologies greatly facilitate our lives, making it easier, simpler and more convenient. Among the variety of such innovations, an important place is occupied by tools that make it easy to navigate the terrain, build a convenient route to a particular geographic point, and find toponyms and other topographical objects on the map. One of the options for finding the desired object on the map is to search for it using geographic coordinates. And in this material I will tell you how to search by coordinates on Yandex Map, and what are the features of this search.
As you know, in the modern digital market of cartographic services there are several competing companies that offer the user the ability to search for a point by coordinates. The list of such services includes the popular “ Google Maps", "Yandex.Maps", "2GIS", (specialization in detailing cities), "Bing Maps", "HERE WeGo", "OpenStreetMap" the previously existing "Yahoo! Maps" (now closed).
The main competitors on Russian market are " Google.Maps" And " Yandex maps" If using maps from Google is preferable on a global scale, then in the vastness of Russia we would recommend using the Yandex company’s service. The latter provides better coverage of Russia, has high level details, boasts a special tool for editing maps by users called “People's Map”, displays existing traffic jams in domestic cities, works well with “Geocoder”, and has other useful features.
To determine your location in the Russian Federation, it is better to use Yandex.Maps At the same time, you can use the Yandex.Maps functionality either using a regular desktop browser on a PC or by installing the Yandex.Maps mobile app to your phone (for example, from the Play Market).
Search by latitude and longitude
If you are faced with the question of searching for any geographical place on the map, or there is a need to point out some place on the map to another person, then you should use the method of determining the location of a geographical object by its coordinates, including latitude or longitude.
Let me remind the reader that latitude coordinates show the location of the desired object in relation to the North and South Pole (i.e. it is a point between north and south), and longitude coordinates determine the location of the object between east and west.
The usual zero latitude is the equator, therefore the south pole is at 90 degrees south latitude, and the north pole is at 90 degrees north latitude.
In this case, northern latitude is designated by the letter “N” (Nord), South – by the letter “S” (South), western longitude by the letter “W” (West), and eastern longitude by the letter “E” (East). ).
Find a place by coordinates on the Yandex Map
To determine the latitude and longitude coordinates of an object, just open “Yandex.Maps”, find the object we need on the map, and click on it with the cursor. A small window will immediately open next to the cursor, informing about the selected object and indicating its latitude and longitude coordinates.
Now, to find this object on the map, it will be enough to write down these numerical values, and then simply enter them separated by commas in the “Yandex.Maps” search bar and press enter. The map will immediately move to the given location and point you to the object specified by the entered coordinates.
It is most convenient to share such coordinates while somewhere in nature; the other party will easily find your location simply by entering your coordinates into the Yandex.Maps search bar.
In addition to finding the desired point by latitude and longitude, the Yandex.Maps functionality makes it possible to build a pedestrian, car, or bus route to it. To do this, just enter the latitude and longitude numbers of the object you need into the search bar, click on enter, and after it appears on the screen, click on the button on the left “Build a route”.
Click on “Build route” to build various options route to the desired geographical point You will need to enter the coordinates of the starting point of your path (or type its address), and the service will automatically route the most convenient route to it. optimal route, and will also indicate the approximate travel time and mileage.
Conclusion
If you need to search by your coordinates on Yandex Map, then it will be enough to enter the coordinates of the desired object by latitude and longitude in the search bar, and then press enter. If you just need to get the coordinates of the object you need, it will be enough to find it on Yandex.Map, click on it, and the necessary latitude and longitude coordinates will immediately be displayed in the sign that appears on the left.
A system of geographic coordinates is necessary in order to accurately determine the location of an object on the Earth's surface. As you know, this system consists of geographic latitude and longitude. The first element of this system is the angle between the local zenith (noon) and the equatorial plane, ranging from 0 to 90 degrees west or east of the equatorial boundary. Longitude is the angle formed by two planes: the meridian passing through a given point in the area and the Greenwich meridian, i.e. zero point. From the latter, the longitude count begins, ranging from 0 to 180 degrees east and west (eastern and western longitude). Knowing how to navigate the terrain using latitude and longitude will help you communicate your exact coordinates in the event of an emergency, when you find yourself in an unfamiliar place that is not indicated on the map, or lost in the forest. You can learn more about how you can determine the latitude and longitude of your location.
Clock for determining location by latitude and longitude
How to determine a place by latitude and longitude
Definition of local geographic longitude carried out using a regular watch. To do this, it is necessary to set on them the exact time of the location in this moment. Then you should determine the time of local noon, a time-tested method will help with this: you need to find a meter or one and a half meter stick and stick it vertically into the ground. The length of the line of the falling shadow will indicate the time intervals that need to be detected. The moment when the shadow is shortest is the local zenith, i.e. The gnomon shows exactly 12 noon, and the direction of the shadow is from south to north.
At this time, you need to check the time on your watch - this will be Greenwich Mean Time. From this value you need to subtract the indicator that is taken from the table of the equation of time. This correction arises due to the variability of the angular velocity of movement and the dependence on the time of year. Taking this correction into account, the average Greenwich time is converted to true solar time. The resulting difference between this solar time (i.e. 12 hours) and Greenwich time, taking into account the correction, must be converted into a degree value. To do this, you need to know that in one hour the Earth rotates by 15 degrees (if you divide 360 degrees by 24 hours) of longitude, or by 1 degree in four minutes. If noon in a given area occurs before Greenwich, indicate eastern longitude in your calculations; if later, then western longitude. The closer the coordinates of the desired area are to the polar regions, the more accurate the longitude measurements will be.
Once the longitude value has been found, you can begin to determine the latitude value of a specific area. First you need to determine the length of daylight hours, which begins with sunrise and ends with sunset. Next, you need to create a nomogram, i.e. determination of latitude: on the left side the value of daylight hours is indicated, on the right - the date. If you combine these values, you can determine where latitude intersects with the midpoint. The location found will indicate the local latitude. When determining latitude relative to the southern hemisphere, it is necessary to add 6 months to the required date. The second method is to find latitude using a conventional protractor: for this, a plumb line (thread with a weight) is fixed in the center of this instrument, and its base is pointed at the North Star. The angle formed by the plumb line and the base of the protractor must be reduced by 90 degrees, i.e. subtract this value from its value. The value of this angle shows the height of the North Star, i.e. the height of the pole above the horizon. Since geographic latitude is equal to the magnitude of the pole above the horizon of a particular place, this value will indicate its degree.
