There are many different coordinate systems. All of them are used to determine the position of points on the earth's surface. This includes mainly geographic coordinates, flat rectangular and polar coordinates. In general, it is customary to call coordinates angular and linear quantities that define points on a surface or in space.

Geographic coordinates are angular values ​​- latitude and longitude, which determine the position of a point on the globe. Geographic latitude is the angle formed by the plane of the equator and a plumb line at a given point on the earth's surface. This angle value shows how far a particular point on the globe is north or south of the equator.

If the point is located in the Northern Hemisphere, then its geographical latitude will be called northern, and if in the Southern Hemisphere - southern latitude. The latitude of points located on the equator is zero degrees, and at the poles (North and South) - 90 degrees.

Geographic longitude is also an angle, but formed by the plane of the meridian, taken as the initial (zero), and the plane of the meridian passing through the given point. For the uniformity of the definition, it was agreed to consider the meridian passing through the astronomical observatory in Greenwich (near London) as the initial meridian and call it Greenwich.

All points located to the east from it will have eastern longitude (up to the meridian of 180 degrees), and to the west of the initial one - western longitude. The figure below shows how to determine the position of point A on the earth's surface if its geographical coordinates (latitude and longitude) are known.

Note that the difference in longitudes of two points on Earth shows not only their relative position with respect to the zero meridian, but also the difference in these points at the same moment. The fact is that every 15 degrees (24th part of the circle) in longitude is equal to one hour of time. Based on this, it is possible to determine the difference in time at these two points by geographical longitude.

For example.

Moscow has a longitude of 37°37′ (East), and Khabarovsk -135°05′, that is, lies to the east of 97°28′. What time do these cities have at the same moment? Simple calculations show that if it is 13:00 in Moscow, then it is 19:30 in Khabarovsk.

The figure below shows the design of the sheet frame of any map. As can be seen from the figure, in the corners of this map, the longitude of the meridians and the latitude of the parallels that form the frame of the sheet of this map are signed.

On all sides, the frame has scales divided into minutes. For both latitude and longitude. Moreover, each minute is divided by dots into 6 equal sections, which correspond to 10 seconds of longitude or latitude.

Thus, in order to determine the latitude of any point M on the map, it is necessary to draw a line through this point parallel to the lower or upper frame of the map, and read the corresponding degrees, minutes, seconds on the latitude scale to the right or left. In our example, point M has a latitude of 45°31’30”.

Similarly, drawing a vertical line through the point M parallel to the lateral (closest to this point) meridian of the border of this sheet of the map, we read the longitude (east) equal to 43 ° 31'18 ".

Drawing a point on a topographic map according to given geographical coordinates.

Drawing a point on the map according to the given geographical coordinates is carried out in the reverse order. First, the indicated geographical coordinates are found on the scales, and then parallel and perpendicular lines are drawn through them. Intersecting them on will show the point with the given geographic coordinates.

Based on the book "The map and the compass are my friends."
Klimenko A.I.

Coordinates called angular and linear quantities (numbers) that determine the position of a point on a surface or in space.

In topography, such coordinate systems are used that allow the most simple and unambiguous determination of the position of points on the earth's surface, both from the results of direct measurements on the ground and using maps. These 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 the object on the earth's surface relative to the origin of coordinates - the point of intersection of the initial (Greenwich) meridian with the equator. On the 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, while the northern and southern sides are parallels. In the corners of the map sheet, the geographical coordinates of the points of intersection of the sides of the frame are signed.

Rice. 1. The 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. For the beginning, in our country and in most other states, the point of intersection of the initial (Greenwich) meridian with the equator is accepted. Being, therefore, the same for our entire planet, the system of geographical coordinates is convenient for solving problems of determining the relative position of objects located at considerable 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, such as ballistic missiles, aviation, etc.

Planar rectangular coordinates(Fig. 2) - linear quantities that determine the position of the object on the 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 system of flat rectangular coordinates is zonal; it is set for each six-degree zone into which the Earth's surface is divided when depicted on maps in the Gaussian projection, and is intended to indicate the position of images of points on the earth's surface on a plane (map) in this projection.

The origin of coordinates in the zone is the point of intersection of the axial meridian with the equator, relative to which the position of all other points of the zone is determined in a linear measure. The origin of the zone coordinates 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 making calculations both when working on the ground and on the map. Therefore, this system finds the widest application in the troops. Rectangular coordinates indicate the position of terrain points, their battle formations and targets, with their help they determine the relative position of objects within one coordinate zone or in adjacent sections 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, in target designation, marking landmarks and targets, drawing up terrain maps, etc. These systems can be associated with systems of rectangular and geographical coordinates.

2. Determination of geographical coordinates and mapping of objects by known coordinates

The geographical coordinates of a point located on the map are determined from the parallels and meridians closest to it, the latitude and longitude of which are known.

The frame of the topographic map 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. Determination of the geographical coordinates of a point on the map (point A) and drawing a point on the map by geographical 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, 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 obtained (measured) value of minutes and seconds (0 "27") with the latitude of the southwestern corner of the frame - 54 ° 30 ".

Latitude points on the map will be equal to: 54°30"+0"27" = 54°30"27".

Longitude defined in a similar way.

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 obtained (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. Put any point on the map according to the given geographical coordinates.

For example, point B latitude: 54°31 "08", longitude 45°01 "41".

To map a point in longitude, it is necessary to draw a true meridian through a given point, for which 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 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. The 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 the 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 the 1:500000 map, only the exits of the coordinate grid lines are plotted on the inner frame of each sheet after 2 cm (10 km on the ground). If necessary, coordinate lines can be drawn on the map along these exits.

On topographic maps, the values ​​of the abscissas and ordinates of the coordinate lines (Fig. 2) are signed at the exits of the lines behind the inner frame of the sheet and nine places on each sheet of the map. The full values ​​of abscissas and ordinates 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 rest of the coordinate lines are signed in abbreviated form with two digits (tens and units of kilometers). Signatures near the horizontal lines of the coordinate grid correspond to distances from the y-axis in kilometers.

Signatures 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, conditionally moved to the west of the zone's central meridian by 500 km. For example, the signature 6740 means: 6 - zone number, 740 - distance from the conditional origin in kilometers.

The outputs of the coordinate lines are given on the outer frame ( additional grid) coordinate systems of the adjacent zone.

4. Determination of rectangular coordinates of points. Drawing points on the map by their coordinates

On the 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).

For this you need:

• write X - digitization of the lower kilometer line of the square in which point B is located, i.e. 6657 km;
• measure along the perpendicular the distance from the lower kilometer line of the square to point B and, using the linear scale of the map, determine the value 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 the Y value - the 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. Put the target on the map according to the given coordinates.

For example, point G by coordinates: X=6658725 Y=7362360.

For this you need:

• find the square in which the point G is located by the value of whole kilometers, i.e. 5862;
• set aside from the lower left corner of the square a segment on the scale of the map, equal to the difference between the abscissa of the target and the lower side of the square - 725 m;
• from the obtained point along the perpendicular to the right, set aside a segment equal to the difference in 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 a point on the map using rectangular coordinates (point D)

5. Accuracy of determining coordinates on maps of various scales

The accuracy of determining geographical coordinates on maps 1:25000-1:200000 is about 2 and 10 "" respectively.

The accuracy of determining the rectangular coordinates of points on a map is limited not only by its scale, but also by the magnitude of the errors allowed when shooting or compiling a map and plotting various points and terrain objects on it

Geodetic points and are plotted most accurately (with an error not exceeding 0.2 mm) on the map. objects that stand out most sharply on the ground and are visible from afar, having the value 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 a scale of 1:25000 - with an accuracy of 5-7 m, for a map of a scale of 1:50000 - with an accuracy of -10- 15 m, for a map at a scale of 1:100000 - with an accuracy of 20-30 m.

The remaining landmarks and contour points are plotted on the map, and, therefore, are determined from it with an error of up to 0.5 mm, and points related to contours that are not clearly expressed 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 systems of polar and bipolar coordinates, mapping objects in direction and distance, in two angles or in two distances

System flat polar coordinates(Fig. 3, a) consists of a 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 the 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 task being solved, an observation post, a firing position, a starting point for movement, etc. are taken as a pole, and a geographic (true) meridian, a magnetic meridian (the direction of a magnetic compass needle) or a direction to some landmark is taken as a polar axis .

These coordinates can be either two position angles that determine directions from points A and B to the desired point M, or distances D1=AM and D2=BM to it. The position angles, 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 initial ones. For example, in the second case, the location of the 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 serif. The position of any point M relative to the two data on the map (terrain) points A and B is determined by the coordinates that are measured on the map or on the terrain.

Drawing the detected object on the 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) will be mapped.

Having found an object (target), you must first determine exactly what is detected by various signs. Then, without stopping the observation of the object and without revealing yourself, put the object on the map. There are several ways to plot an object on a map.

visually: Places a feature on the map when it is close to a known landmark.

By direction and distance: to do this, you need to orient the map, find your point of standing on it, sight the direction to the detected object on the map 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 commensurate it with the scale of the map.

Rice. 4. Drawing a target on the map with a straight cut from two points.

If in this way it is graphically impossible to solve the problem (the enemy interferes, poor visibility, etc.), then you need to accurately measure the azimuth to the object, then translate it into a directional angle and draw a direction on the map from the standing point, on which to plot the distance to the object.

To get the directional angle, you need to add the magnetic declination of this map (direction correction) to the magnetic azimuth.

straight serif. In this way, an object is put on a map of 2-3 points from which it is possible to observe it. To do this, from each selected point, the direction to the object is drawn on the oriented map, then the intersection of straight lines determines the location of the object.

7. Ways of target designation on the map: in graphical coordinates, 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, from a conditional line, by 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 subunits and fire in combat or for organizing combat.

Target designation in geographic coordinates It is used very rarely and only in those cases when the targets are removed from a given point on the map at a considerable distance, expressed in tens or hundreds of kilometers. In this case, geographical 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, mark the position of the target in latitude and longitude with a prick of a compass. From these marks, perpendiculars are lowered into the depth of the sheet of the topographic map until they intersect (commander's rulers, 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 rectangular coordinates it is enough to indicate on the map the square of the grid in which the object is located. The square is always indicated by the numbers of kilometer lines, the intersection of which forms the southwestern (lower left) corner. When indicating the square, the cards follow the rule: first they name two numbers signed at the horizontal line (at the western side), that is, the “X” coordinate, and then two numbers at the vertical line (south side of the sheet), that is, the “Y” coordinate. In this case, "X" and "Y" are not spoken. For example, enemy tanks are spotted. 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 the full coordinates. For example, it is required to determine the coordinates of a road sign in square 8803 on a map at a scale of 1:50000. First, determine what is the distance from the lower 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. In the same way, we determine the vertical line 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 required to clarify the position of the target in a square, then target designation is used by letter or number inside the square of the kilometer grid.

When targeting in a 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.

The second way - digital way target designation inside the kilometer grid square (target designation by snail ). This method got its name from the arrangement of conditional digital squares inside the square of the kilometer grid. They are arranged as if in a spiral, while the square is divided into 9 parts.

When targeting 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, a height of 51.8 (5863-A) or a 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 nearest landmark to the target is first called, then the angle between the direction to the landmark and the direction to the target in goniometer divisions (measured with binoculars) and the distance to the target in meters. For example: "Landmark two, forty to the right, further two hundred, at a separate bush - a machine gun."

target designation from the conditional line usually used in 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 indicated by letters, divided into centimeter divisions and numbered starting from zero. Such a construction is done on the maps of both the transmitting and receiving target designation.

Target designation from a conditional line is usually used in 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 indicated by letters, divided into centimeter divisions and numbered starting from zero.

Rice. 5. Target designation from a conditional line

Such a construction is done on the maps of both the 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 segment of the perpendicular from the conditional line to the target.

When targeting, the conditional 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: “Direct AC, five, seven; zero to the right, six - NP.

Target designation from a conditional line can be issued by indicating the direction to the target at an angle from the conditional line and the distance to the target, for example: "Direct 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 pre-prepared points (marked objects).

Each student determines geographic and rectangular coordinates (maps objects at known coordinates).

Target designation methods on the map are practiced: 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, in azimuth and range of the target.

Determination of coordinates independently.

Determining latitude and longitude on a map or on a globe is one of the most accurate ways to determine the location of a large object. Determination of geographical coordinates, both historically and at the moment, is relevant in navigation, for orientation in the area, when moving on foot or in transport.

Each object, which is distinguished by a stable location, can have not only its own postal address, but also a geographical address, reflected precisely in latitude and longitude. When asked how to determine the latitude and longitude on the map, the video and text instructions are quite detailed, it is not difficult to answer this question, and in order to use knowledge in practice, you just need to pay due attention to the instructions that people have been using for hundreds of years.

horizontal lines

Latitude is expressed in degrees indicated on the map, and represents the distance to a particular point, relative to the Equator, it can be either positive or negative, respectively - North and South. Southern latitudes - from the Equator to the South Pole (negative), Northern - from the Equator to the North Pole (positive).

The Equator is taken as the latitude of the zero value, its value increases from the Equator to the poles and can have a value from 0 ° to 90 °, both in one direction and in the other direction.

North latitude is indicated by the English letter N (from North), South - S (from South).

vertical lines

Longitude is expressed in degrees and shows the distance from any point to the position of Greenwich (zero meridian), it can have a positive and negative value, and is also divided into hemispheres. To the west of Greenwich - positive, Western. To the east - negative or Eastern.

The entire circumference of the Earth is defined as 360°, with 180° making up the Western and Eastern hemispheres. Longitude is higher the farther it is from Greenwich (zero meridian) and can range from 0 to 180°.

The designation of the western longitude comes from the English word West, by the first letter - W. And the eastern one is indicated by the word East and the letter E.

Determination of coordinates - simply and quickly

The step between degrees is 111.11 kilometers, minutes and seconds are fractional degrees, allowing you to determine the position of the object with an accuracy of several meters (5-20 approximately).

• To find out the latitude of a point, it is necessary to establish whether it belongs to the northern or southern hemisphere (above or below the Equator). Parallels in tens of degrees are signed on the right or left side of the map (or both). It is necessary to establish between which parallels the desired position is located. Next, you need to use measuring instruments or marks on the map to set the distance from the selected point to the nearest parallel from the Equator in degrees;
• To determine the longitude of a point, you must first find out its position on the map relative to Greenwich - the western hemisphere is located to the right of the zero meridian, and the eastern hemisphere is located to the left. Longitude can be labeled on the top and bottom of the map, as well as at the point of intersection with the Equator. It is necessary to set the distance of the desired position to the nearest meridian from Greenwich;
• The intersection point between meridians and parallels is the geographic coordinates of the selected point.

It is worth considering that you can set the exact location of the point if you have a sufficiently detailed map, where it is possible to use not only degrees, but also minutes and seconds. A degree is 111 kilometers, and its minute is already 1.85 kilometers, a second allows you to specify the position of a point up to 30 meters.

How to determine the latitude and longitude on the Yandex map and Google map

In order to find out the characteristics of the area in the Google mapping system, you need to move the mouse over the area of ​​interest, while you can adjust the scale using the mouse wheel and move the map by pressing the left mouse button and moving the device in the desired direction. After clicking on the desired position with the right mouse button, you need to select the item “what is located here” in the drop-down menu, the system will immediately enter the result in the search line above and display information about the objects located in the specified area and other characteristics of the area.

Geographic longitude and latitude are used to accurately determine the physical location of any object on the globe. The easiest way to find geographic coordinates is to use a geographic map. This method requires some theoretical knowledge for its implementation. How to determine the longitude and latitude is described in the article.

Geographical coordinates

Coordinates in geography are a system in which each point on the surface of our planet is assigned a set of numbers and symbols that allows you to accurately determine the position of this point. Geographical coordinates are expressed in three numbers - this is latitude, longitude and height above sea level. The first two coordinates, that is, latitude and longitude, are most often used in various geographical tasks. The origin of the report in the geographic coordinate system is at the center of the Earth. Spherical coordinates are used to represent latitude and longitude, which are expressed in degrees.

Before considering the question of how to determine longitude and latitude by geography, you should understand these concepts in more detail.

The concept of latitude

The latitude of a particular point on the surface of the Earth is understood as the angle between the equatorial plane and the line connecting this point with the center of the Earth. Through all points on having the same latitude, you can draw a plane that will be parallel to the plane of the equator.

The plane of the equator is the zero parallel, that is, its latitude is 0 °, and it divides the entire globe into the southern and northern hemispheres. Accordingly, the north pole lies on parallel 90° north latitude and the south pole lies on parallel 90° south latitude. The distance that corresponds to 1° when moving along a particular parallel depends on which parallel it is. With increasing latitude when moving north or south, this distance decreases. Thus is 0°. Knowing that the circumference of the Earth at the latitude of the equator has a length of 40075.017 km, we obtain a length of 1 ° along this parallel equal to 111.319 km.

Latitude indicates how far north or south of the equator a given point lies on the Earth's surface.

The concept of longitude

The longitude of a particular point on the surface of the Earth is understood as the angle between the plane passing through this point and the axis of rotation of the Earth, and the plane of the prime meridian. According to the settlement agreement, the meridian is supposed to be zero, which passes through the Royal Observatory in Greenwich, located in the southeast in England. The Greenwich meridian divides the globe into east and

Thus, each line of longitude passes through the north and south poles. The lengths of all meridians are equal and amount to 40007.161 km. If we compare this figure with the length of the zero parallel, then we can say that the geometric shape of the planet Earth is a ball flattened from the poles.

Longitude shows how far west or east of the zero (Greenwich) meridian lies a specific point on Earth. If latitude has a maximum value of 90° (latitude of the poles), then the maximum value of longitude is 180° west or east of the prime meridian. The 180° meridian is known as the international date line.

One can ask an interesting question, the longitude of which points cannot be determined. Based on the definition of the meridian, we get that all 360 meridians pass through two points on the surface of our planet, these points are the south and north poles.

Geographic degree

From the above figures it can be seen that 1 ° on the Earth's surface corresponds to a distance of more than 100 km, both along the parallel and along the meridian. For more accurate coordinates of the object, the degree is divided into tenths and hundredths, for example, they talk about 35.79 north latitude. In this form, information is provided by satellite navigation systems such as GPS.

Ordinary geographical and topographic maps represent fractions of a degree in the form of minutes and seconds. So, each degree is divided into 60 minutes (denoted by 60"), and each minute is divided into 60 seconds (denoted by 60""). Here you can draw an analogy with the representation of the measurement of time.

Getting to know the map

To understand how to determine the geographical latitude and longitude on the map, you must first familiarize yourself with it. In particular, you need to figure out how the coordinates of longitude and latitude are represented on it. First, the top of the map shows the northern hemisphere, the bottom shows the southern. The numbers on the left and right of the edge of the map indicate latitude, and the numbers at the top and bottom of the map are longitude coordinates.

Before you determine the coordinates of latitude and longitude, you must remember that they are presented on the map in degrees, minutes and seconds. Do not confuse this system of units with decimal degrees. For example, 15" = 0.25°, 30" = 0.5°, 45"" = 0.75".

Using a geographic map to determine longitude and latitude

Let us explain in detail how to determine longitude and latitude by geography using a map. To do this, you first need to purchase a standard geographic map. This map can be a map of a small area, region, country, continent, or the whole world. To understand which card to deal with, you should read its name. At the bottom, under the name, the limits of latitudes and longitudes, which are presented on the map, can be given.

After that, you need to select some point on the map, some object that needs to be marked in some way, for example, with a pencil. How to determine the longitude of an object located at a selected point, and how to determine its latitude? The first step is to find the vertical and horizontal lines that lie closest to the selected point. These lines are the latitude and longitude, the numerical values ​​​​of which can be viewed at the edges of the map. Assume that the chosen point lies between 10° and 11° north latitude and 67° and 68° west longitude.

Thus, we know how to determine the geographic latitude and longitude of the object selected on the map with the accuracy that the map provides. In this case, the accuracy is 0.5°, both in latitude and longitude.

Determination of the exact value of geographical coordinates

How to determine the longitude and latitude of a point more precisely than 0.5 °? First you need to find out what scale the map with which you are working is. Usually, a scale bar is indicated in one of the corners of the map, showing the correspondence of distances on the map to distances in geographical coordinates and in kilometers on the ground.

After the scale bar is found, it is necessary to take a simple ruler with millimeter divisions and measure the distance on the scale bar. Let in this example, 50 mm corresponds to 1 ° latitude and 40 mm - 1 ° longitude.

Now we position the ruler so that it is parallel to the lines of longitude drawn on the map, and measure the distance from the point in question to one of the nearest parallels, for example, the distance to the 11 ° parallel is 35 mm. We make up a simple proportion and find that this distance corresponds to 0.3 ° from the 10 ° parallel. Thus, the latitude of the point under consideration is +10.3° (the plus sign means north latitude).

Similar actions should be done for longitude. To do this, place the ruler parallel to the lines of latitude and measure the distance to the nearest meridian from the selected point on the map, for example, this distance is 10 mm to the meridian of 67 ° west longitude. According to the rules of proportion, we obtain that the longitude of the object in question is -67.25 ° (the minus sign means longitude west).

Convert received degrees to minutes and seconds

As stated above, 1° = 60" = 3600"". Using this information and the rule of proportion, we find that 10.3° corresponds to 10°18"0"". For the longitude value, we get: 67.25 ° = 67 ° 15 "0"". In this case, the proportion was used once for the longitude and latitude for the conversion. However, in the general case, when fractional minutes are obtained after using the proportion once, it follows use the proportion a second time to get the value of incremental seconds. Note that the accuracy of determining the coordinates to 1 "corresponds to an accuracy on the surface of the globe equal to 30 meters.

Recording received coordinates

After the question of how to determine the longitude of an object and its latitude has been resolved, and the coordinates of the selected point have been determined, they should be written down correctly. The standard notation is to indicate the longitude after the latitude. Both values ​​must be specified with as many decimal places as possible, since the accuracy of the object location depends on this.

Certain coordinates can be represented in two different formats:

1. Using only the degree icon, e.g. +10.3°, -67.25°.
2. Using minutes and seconds, for example, 10°18"0"" North, 67°15"0"" West.

It should be noted that when representing geographic coordinates in degrees only, the words "North (South) latitude" and "East (West) longitude" are replaced by the appropriate plus or minus sign.

Video lesson “Geographical latitude and geographical longitude. Geographical coordinates will help you get an idea of ​​the geographic latitude and geographic longitude. The teacher will tell you how to correctly determine the geographical coordinates.

Geographic latitude- the length of the arc in degrees from the equator to the given point.

To determine the latitude of an object, you need to find the parallel on which this object is located.

For example, the latitude of Moscow is 55 degrees and 45 minutes north latitude, it is written as follows: Moscow 55 ° 45 "N; New York latitude - 40 ° 43" N; Sydney - 33°52"S

Geographic longitude is determined by meridians. Longitude can be western (from 0 meridian west to 180 meridian) and eastern (from 0 meridian east to 180 meridian). Longitudes are measured in degrees and minutes. Geographic longitude can have values ​​from 0 to 180 degrees.

Geographic longitude- length of the arc of the equator in degrees from the initial meridian (0 degrees) to the meridian of the given point.

The prime meridian is the Greenwich meridian (0 degrees).

Rice. 2. Definition of longitudes ()

To determine longitude, you need to find the meridian on which the given object is located.

For example, the longitude of Moscow is 37 degrees and 37 minutes of east longitude, it is written as follows: 37 ° 37 "E; the longitude of Mexico City is 99 ° 08" W.

Rice. 3. Geographic latitude and geographic longitude

To accurately determine the location of an object on the surface of the Earth, you need to know its geographic latitude and geographic longitude.

Geographical coordinates- quantities that determine the position of a point on the earth's surface using latitudes and longitudes.

For example, Moscow has the following geographic coordinates: 55°45" N and 37°37" E. The city of Beijing has the following coordinates: 39°56′ N 116°24′ E The latitude value is written first.

Sometimes you need to find an object by already given coordinates, for this you must first assume in which hemispheres this object is located.

Homework

Paragraphs 12, 13.

1. What is geographic latitude and longitude?

Bibliography

Main

1. Initial course of geography: Proc. for 6 cells. general education institutions / T.P. Gerasimova, N.P. Neklyukov. - 10th ed., stereotype. - M.: Bustard, 2010. - 176 p.

2. Geography. Grade 6: atlas. - 3rd ed., stereotype. - M.: Bustard, DIK, 2011. - 32 p.

3. Geography. Grade 6: atlas. - 4th ed., stereotype. - M.: Bustard, DIK, 2013. - 32 p.

4. Geography. 6 cells: cont. cards. - M.: DIK, Bustard, 2012. - 16 p.

Encyclopedias, dictionaries, reference books and statistical collections

1. Geography. Modern illustrated encyclopedia / A.P. Gorkin. - M.: Rosmen-Press, 2006. - 624 p.

Literature for preparing for the GIA and the Unified State Examination

1. Geography: an initial course. Tests. Proc. allowance for students 6 cells. - M.: Humanit. ed. center VLADOS, 2011. - 144 p.

2. Tests. Geography. Grades 6-10: Teaching aid / A.A. Letyagin. - M .: LLC "Agency" KRPA "Olimp": "Astrel", "AST", 2001. - 284 p.

Materials on the Internet

1. Federal Institute of Pedagogical Measurements ().

2. Russian Geographical Society ().