They are necessary in order to find a specific object on a globe or geographical map. Geographic coordinates include geographic latitude , geographic longitude And absoluteheight .

All geographical features on Earth, in addition to the poles, they have latitude and longitude. All meridians of the Earth at the pole converge at one point. Therefore, the North and South Poles only have a latitude of 90 degrees.

Maps with parallels and meridians marked on them help sailors find their way among the vast expanses of the ocean. From them you can determine where the ship is, how long it still has to sail, and what lands it will meet along the way. Sailors and travelers determine the latitude and longitude of an area using special instruments, working with which requires knowledge of mathematics and astronomy.

Geographic latitude points are the magnitude of the arc in degrees between the equator and this point. The geographic latitude of any place on the globe is expressed in degrees, which are counted from the Equator (0°) to the poles (90°).

To determine the geographic latitude of a place on a map or globe, you need to know what parallel it is on. The value of parallels from 0 degrees at the equator to 90 degrees at the pole is written along the prime, Greenwich meridian or on the side of the map frame. All points on the earth's surface north of the equator have a northern latitude, all points in the southern hemisphere have a southern latitude.

On the map of the hemispheres in the atlas, parallels are drawn through 20°, therefore, not all points of the globe are on the designated parallels.

Determination of latitude

The Suez Canal is located at 30° north latitude (abbreviated: N), for example, a parallel of 60 degrees runs through St. Petersburg. This means that the city lies at 60 degrees north latitude (N).

Moscow, located in the Northern Hemisphere, is located between 40° N. w. and 60° N. w. It is not difficult to guess that the latitude of Moscow is approximately 55.5° N. w. (55 degrees 30 minutes N). Both Moscow, St. Petersburg, and the Suez Canal are located north of the Equator, so their latitude is north; any point south of the Equator will have a southern latitude (abbreviated: S). Thus, Kerguelen Island in the Indian Ocean is located at 50° south. w.

A parallel of 30 degrees runs through the center of the Drake Passage in the Southern Hemisphere. The latitude of Lake Victoria in Africa is 0 degrees.

To accurately determine a point on a globe or on a map, you need to know, in addition to the geographic latitude, the geographic longitude of this point.

Geographical longitude points is the magnitude of the arc in degrees from the prime meridian to this point earth's surface.

Like latitude, longitude is expressed in degrees, which are measured from the prime meridian. The prime meridian was chosen arbitrarily, and it passes through the Greenwich Observatory, located near the city of London. The Greenwich meridian on the globe and geographical map is shown as a thicker line, and at its intersection with the equator it is written: 0° (degrees). All other meridians are also labeled in degrees at the equator. These degrees increase in both directions from the zero, Greenwich, meridian and reach a value of 180 degrees on the other side of the Earth. The 180th meridian is also shown with a thick line. The two halves of the Earth's circumference - the Eastern and Western Hemispheres - are separated by 180 degrees.

Determination of longitude

To the east of the Greenwich meridian there will be eastern longitude (abbreviated: E.L.), to the west - western longitude (W.L.). Degrees of longitude on a globe and a map of the hemispheres are indicated at the Equator. Thus, the Suez Canal is located at 32° east. d., and the Strait of Gibraltar - already at 5° W. d. Material from the site

Through city ​​of St. Petersburg passes the 30 degree meridian in the Eastern Hemisphere. This means that the longitude of this city is 30 degrees east (30° east).

Through Bering Strait, which divides Eurasia and North America, passes the 170th meridian of the Western Hemisphere. This means its longitude is 170° west longitude (170° west longitude).

Moscow city is located in the Eastern Hemisphere between the meridians of 30 degrees and 40 degrees. Divide this distance into 10 parts - 10 degrees. The longitude of Moscow will be approximately 37 degrees east longitude. It can be determined more precisely - 37.5° east. Degrees are divided into minutes; there are 60 minutes in one degree. They also say that Moscow is located at 37 degrees 30 minutes east longitude.

Latitude and longitude are necessary to determine position on the globe. Knowing how to read latitude and longitude from a map, you can determine the geographic coordinates of any point on the map. While online maps make it easy to find latitude and longitude with the click of a button, sometimes it's helpful to know how to do this on a paper map. In order to calculate latitude and longitude correctly, you first need to understand what it is. Once you've mastered the basics, you can learn how to identify latitude and longitude markers on a map and determine the coordinates of any point.

Steps

Part 1

Become familiar with the concept of latitude. Latitude is a measure of distance north or south of the equator, which is an imaginary horizontal line equidistant from the poles. The entire Earth is divided by 180 latitude lines located on both sides of the equator, which are called parallels. Parallels run parallel to the equator; on a map they are usually horizontal. 90 of them are north of the equator, another 90 are to the south.

Learn the definition of longitude. Longitude is a measure of the distance east or west of an imaginary line running across the surface of the globe from the North Pole to the South Pole, called the prime meridian. Lines of longitude are a series of lines running from the North Pole to the South Pole, called meridians; on maps they are usually vertical. At all points through which one meridian passes, noon occurs at the same time. There are 360 ​​meridians on Earth, of which 180 are located east of the prime meridian, and the other 180 are located to the west.

Learn the units of latitude and longitude. Latitude and longitude are usually measured in degrees (°), minutes (′), and seconds (″). The total distance from one parallel to another or from one meridian to another is 1°. To make more accurate measurements, each degree can be divided into 60 minutes, and each minute into 60 seconds (thus, there are 3600 seconds in a degree).

Measure latitude and longitude relative to the zero point. When measuring latitude, the starting line is the equator, which has a latitude of 0°. Likewise, the prime meridian is the starting line for measuring longitude, having a longitude of 0°. Any value of latitude or longitude is expressed by how far a given point is from the starting line and in what direction from it it is.

• For example, the latitude of the North Pole is 90° N. w. (N latitude), which means it is 90° north of the equator.
• The antimeridian has a longitude of 180° and can be designated as either western or eastern longitude.
• The Great Sphinx of Giza, Egypt, is located at 29°58′31″ N. w. and 31°8′15″ E. d. (East longitude). This means that it is just south of 30° north of the equator in latitude, and approximately 31° east of the prime meridian in longitude.

Part 2

Finding latitude and longitude coordinates on a map

1. Find a map with latitude and longitude lines. Not all maps show latitude and longitude. You'll most likely find them on maps of large areas, such as maps in an atlas. Among maps of smaller areas, they are most likely to be on maps that are designed to depict terrain particularly accurately, e.g. topographic maps. Keep in mind that in Russia topographic maps at a scale of 1:50,000 and larger are classified.

   Find an object that interests you. Look at the map and find the point or area for which you want to know the coordinates. Mark the specific point that interests you with a pin or pencil.

   Find the latitude and longitude markers on the map. Latitude is indicated on a map by a series of equally spaced horizontal lines running from one side of the map to the other, and longitude by a series of equally spaced vertical lines running from top to bottom. Look at the numbers along the edges of the map - they show the coordinate (latitude or longitude) for each line.

   • Latitudes are shown along the eastern and western borders of the map. Longitudes are shown along its northern and southern boundaries.
   • Depending on the scale of the map you are using, the numbers along the edges of the map may indicate fractions of degrees rather than whole degrees. For example, they may show every minute rather than every degree (for example, 32°0′, 32°1′, and so on).
   • The map must also indicate the position of latitude and longitude relative to the equator and prime meridian, respectively (that is, north or south latitude, west or east longitude).
   • Be careful not to confuse latitude and longitude lines with the kilometer grid, another type of coordinate grid that is also often seen on maps, especially topographic ones. On Russian topographic maps, kilometer line labels are two-digit numbers (without a degree symbol) located along the entire border of the map, and latitude and longitude labels are only available at the corners of the map. Designations may be different in other countries.

2. Use a ruler to mark the latitude of the point of interest. Take a ruler and pencil and draw a horizontal line from the desired point to the western or eastern edge of the map (whichever is closer). Make sure the line you draw is parallel to the closest latitude line on the map.

   Draw another line to mark the longitude of the point. From the same point, draw a straight vertical line with a ruler to the top or bottom edge of the card (whichever is closer). Make sure that the line you draw is parallel to the nearest line of longitude.

3. Determine the latitude and longitude of the point of interest using the latitude and longitude labels. Depending on the scale of the map, you can determine the coordinates of the point of interest to you in degrees, minutes or seconds. Look at the place where the latitude and longitude lines you drew intersect the edge of the map, and determine their coordinates by their position relative to the nearest lines available on the map.

   • If the map you are using shows seconds, find the second mark closest to where the line you drew intersects the edge of the map. For example, if the line is approximately 5″ above the 32°20′ N line. latitude, the desired point has a latitude of approximately 32°20′5″ N. w.
   • If the map shows every minute but not the seconds, you can determine latitude or longitude to the nearest 6 seconds by dividing the space between the lines into tenths. If the line of longitude is 2/10 to the left of the line 120°14′ E. d., which means its longitude is approximately 120°14′12″ E. d.

Geographic longitude and latitude are used to accurately determine the physical location of any object on the globe. The most in a simple way finding geographical coordinates is to use a geographic map. This method requires some theoretical knowledge to implement it. How to determine 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 the precise location of that point to be determined. Geographic coordinates are expressed in three numbers - latitude, longitude and altitude above sea level. The first two coordinates, that is, latitude and longitude, are most often used in various geographical problems. The origin of the report in the geographic coordinate system is at the center of the Earth. To represent latitude and longitude, spherical coordinates are used, 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 specific point on the Earth's surface is understood as the angle between the equatorial plane and the line connecting this point with the center of the Earth. Through all points of the same latitude, you can draw a plane that will be parallel to the plane of the equator.

The equatorial plane 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 at the parallel of 90° north latitude, and the south pole lies at the parallel of 90° south latitude. The distance that corresponds to 1° when moving along a particular parallel depends on what kind of parallel it is. As latitude increases, moving north or south, this distance decreases. Therefore, is 0°. Knowing that the circumference of the Earth at the latitude of the equator has a length of 40075.017 km, we obtain the length of 1° along this parallel equal to 111.319 km.

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

The concept of longitude

The longitude of a specific point on the Earth's surface is understood as the angle between the plane passing through this point and the Earth's axis of rotation, and the plane of the prime meridian. According to the settlement agreement, the zero meridian is the one that passes through the Royal Observatory at Greenwich, located in the southeast of England. The Greenwich meridian divides the globe into eastern 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, we can say that the geometric shape of planet Earth is a ball flattened at the poles.

Longitude shows how far west or east of the prime (Greenwich) meridian a specific point on Earth lies. If latitude has a maximum value of 90° (the 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.

An interesting question to ask is which points cannot have their longitude determined. Based on the definition of a meridian, we find that all 360 meridians pass through two points on the surface of our planet; these points are the south and north poles.

Geographical degree

From the above figures it is clear that 1° on the Earth’s surface corresponds to a distance of more than 100 km, either along a parallel or along a meridian. For more accurate coordinates of an object, the degree is divided into tenths and hundredths, for example, they say 35.79 north latitude. This type of information is provided by satellite navigation systems such as GPS.

Conventional geographic and topographic maps represent fractions of degrees in minutes and seconds. Thus, each degree is divided into 60 minutes (denoted by 60"), and each minute is divided into 60 seconds (denoted by 60"). An analogy can be drawn here with the idea of ​​measuring time.

Getting to know the geographic map

To understand how to determine geographic latitude and longitude on a map, you must first become familiar with it. In particular, you need to understand how longitude and latitude coordinates are represented on it. Firstly, the top part of the map shows the northern hemisphere, the bottom part shows the southern hemisphere. The numbers on the left and right sides of the map indicate latitude, and the numbers on the top and bottom of the map indicate longitude coordinates.

Before determining the latitude and longitude coordinates, you need to remember that they are presented on the map in degrees, minutes and seconds. This system of units should not be confused with decimal degrees. For example, 15" = 0.25°, 30" = 0.5°, 45"" = 0.75".

Using a geographic map to determine longitude and latitude

We will 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, a region, a country, a continent, or the entire world. To understand which card you are dealing with, you should read its name. At the bottom, under the name, the limits of latitude and longitude that are presented on the map can be given.

After this, you need to select a certain 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 latitude and longitude, the numerical values ​​of which can be seen at the edges of the map. Let's assume that the selected 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.

Determining the exact value of geographic coordinates

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

After you have found a scale ruler, you need to take a simple ruler with millimeter divisions and measure the distance on the scale ruler. Let, in the example under consideration, 50 mm correspond to 1° latitude and 40 mm correspond to 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 a simple proportion and find that this distance corresponds to 0.3° from the 10° parallel. Thus, the latitude of the point in question is +10.3° (the plus sign means north latitude).

Similar steps 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, let’s say this distance is 10 mm to the meridian 67° west longitude. According to the rules of proportion, we find that the longitude of the object in question is -67.25° (the minus sign means western longitude).

Converting the received degrees into 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 for conversion once for longitude and latitude. However, in the general case, when after using the proportion once fractional values ​​of minutes are obtained, it should be use the proportion a second time to get the value of incremental seconds. Note that the accuracy of determining coordinates up 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 answered, and the coordinates of the selected point have been determined, they should be written down correctly. The standard form of notation is to indicate longitude after latitude. Both values ​​must be specified as closely as possible a large number decimal places, since the accuracy of the object’s location depends on this.

Defined coordinates can be represented in two different formats:

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

It should be noted that in the case of representing geographic coordinates only using degrees, the words “north (south) latitude” and “east (west) longitude” are replaced by the corresponding plus or minus sign.

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 northern and south poles and spread in east and west 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.

Let us remind you that geographic coordinates (latitude and longitude) – these are angular quantities that determine the position of objects on the earth’s surface and on the map. In this case, the latitude of a point is the angle formed by the equatorial plane and the normal to the surface of the earth's ellipsoid passing through this point. Latitudes are counted along the meridian arc from the equator to the poles from 0 to 90°; In the northern hemisphere, latitudes are called northern (positive), in the southern hemisphere - southern (negative).

The longitude of a point is the dihedral angle between the plane of the Greenwich meridian and the meridian plane of the given point. Longitude is calculated along the arc of the equator or parallel in both directions from the prime meridian, from 0 to 180°. The longitude of points located east of Greenwich to 180° is called eastern (positive), to the west - western (negative).

Geographical (cartographic, degree) grid - image on the map of lines of parallels and meridians; used to determine geographic (geodesic) coordinates of points (objects) and target designation. On topographic maps, the lines of parallels and meridians are the inner frames of the sheets; their latitude and longitude are signed on the corners of each sheet. The geographic grid is fully shown only on topographic maps of scale 1:500000 (parallels are drawn through 30", and meridians - through 20") and 1:1000000 (parallels are drawn through 1°, and meridians - through 40"). Inside each sheet of the map there is The lines of parallels and meridians are marked with their latitude and longitude, which make it possible to determine geographic coordinates on a large map.

On maps of scales 1:25000, 1:50000, 1:100000 and 1:200000, the sides of the frames are divided into segments equal to degree measure 1". Minute segments are shaded every other and divided by dots (with the exception of the 1:200000 scale map) into parts of 10". In addition, inside each sheet of maps of scales 1:50000 and 1:100000 the intersection of the average parallel and meridian is shown and their digitization in degrees and minutes is given, and along the inner frame there are outputs of minute divisions with strokes 2-3 mm long, along which parallels can be drawn and meridians on a map glued together from several sheets.

If the territory for which the map was created is located in the Western Hemisphere, then the inscription “West of Greenwich” is placed in the northwestern corner of the sheet frame to the right of the meridian longitude signature.

Determining the geographic coordinates of a point on a map is carried out using the nearest parallel and meridian, the latitude and longitude of which are known. To do this, on maps of scales 1:25000 - 1:200000, you should first draw a parallel to the south of the point and a meridian to the west, connecting the corresponding strokes on the sides of the sheet frame with lines (Fig. 2.6). Then segments are taken from the drawn lines to the point being determined (Ah 1 Ahh 2 ), apply them to the degree scales on the sides of the frame and make readings. In the example in Fig. 1.2.6, the point A has coordinates B = 54°35"40" north latitude, L= 37°41"30" east longitude.

Plotting a point on a map using geographic coordinates . On the western and eastern sides of the frame of the map sheet, marks corresponding to the latitude of the point are marked with dashes. The latitude count starts from the digitization of the southern side of the frame and continues at minute and second intervals. Then a line is drawn through these lines - parallel to the point.

The meridian of a point passing through a point is constructed in the same way, only its longitude is measured along the southern and northern sides of the frame. The intersection of the parallel and the meridian will indicate the position of this point on the map. Figure 2.6 shows an example of plotting a point on a map M by coordinates B = 54°38.4"N, L= 37°34.4"E

Rice. 2.6 Determining geographic coordinates on a map and plotting points on a map using geographic coordinates