What are parallels and meridians in geography? Degree network, its elements. Geographic coordinates – Knowledge Hypermarket

Degree grid consists of a system of lines (parallels and meridians) and their coordinates. In reality on earth's surface these lines are missing. They are carried out on maps and plans for mathematical calculations and determining the location of an object on the surface of the Earth.

Rice. 1. Parallels and meridians

The direction of the meridian coincides with the direction of the shadow at noon. Meridian- a conventional line drawn on the surface of the Earth from one pole to the other. The magnitude of the arc and circumference of the meridian is measured in degrees. All meridians are equal, intersect at the poles, and have a north-south direction. The length of one degree of each meridian is 111 km (we divide the circumference of the Earth by the number of degrees: 40,000: 360 = 111 km). Knowing this value, it is not difficult to determine the distance along the meridian. For example, the arc length along the meridian is 20 degrees. To find this length in kilometers, you need 20 x 111 = 2220 km.

Meridians are usually labeled at the top or bottom of the map.

The meridian count starts from the prime meridian (0 degrees) - Greenwich.

Rice. 2. Meridians on the map of Russia

Parallels

Parallel– a conventional line drawn along the surface of the Earth parallel to the equator. The direction of the parallel points to west and east. The parallels are drawn not only parallel to the equator, but also parallel to other parallels; they are different in length and do not intersect.

The longest parallel (40,000 km) is the equator (0 degrees).

Rice. 3. Equator on the map

The length of one degree of each parallel can be seen at the map frame.

Length of 1 degree parallels

Rice. 4. Parallels (a) and meridians (b)

Drawing parallels and meridians. Determining their directions

Parallels and meridians can be drawn through any place on the earth's surface. Using parallels and meridians, you can determine the main and intermediate sides of the horizon. The directions “north” and “south” are determined by meridians, and “east” and “west” by parallels. Intersecting, parallels and meridians form a degree network.

References

Main

1. Beginner course Geography: Textbook. for 6th grade. general education institutions / T.P. Gerasimova, N.P. Neklyukova. – 10th ed., stereotype. – M.: Bustard, 2010. – 176 p.

2. Geography. 6th grade: atlas. – 3rd ed., stereotype. – M.: Bustard, DIK, 2011. – 32 p.

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

4. Geography. 6th grade: cont. cards. – M.: DIK, Bustard, 2012. – 16 p.

Encyclopedias, dictionaries, reference books and statistical collections

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

Materials on the Internet

1. Federal Institute pedagogical measurements ().

2. Russian Geographical Society ().

Almost all of you have paid attention to the “mysterious lines” on maps and globes representing latitude (parallels) and longitude (meridians). They form a grid coordinate system by which any place on Earth can be precisely located - and there is nothing mysterious or complicated about it. Parallels and meridians are imaginary lines on the surface of the Earth, and latitude and longitude are their coordinates that determine the position of points on the surface of the Earth. Any point on Earth is the intersection of a parallel and a meridian with latitude and longitude coordinates. This can be most clearly studied using a globe, where these lines are indicated.
But first things first. Two places on Earth are determined by its rotation around its own axis - these are North and South Poles. On globes, the axis is the rod. The North Pole is located in the middle of the North Arctic Ocean which is covered sea ice, and explorers in the old days reached this pole on a sleigh with dogs (it is officially believed that the North Pole was discovered in 1909 by the American Robert Peri). However, since the ice moves slowly, the North Pole is not an actual object, but a mathematical one. The South Pole, on the other side of the planet, has a permanent physical location on the continent of Antarctica, which was also discovered by land explorers (a Norwegian expedition led by Roald Amundsen in 1911). Today both poles can be easily reached by plane.
Halfway between the poles on the “waist” of the Earth there is a large line of a circle, which on the globe is represented as a seam: the junction of the northern and southern hemispheres; this circle line is called - equator. The equator is a line of latitude with a value of zero (0°). Parallel to the equator, above and below it, there are other lines of the circle - these are other latitudes of the Earth. Each latitude has a numerical value, and the scale of these values is measured not in kilometers, but in degrees north and south from the equator to the poles. The poles have the following values: North +90°, and South -90°. Latitudes located above the equator are called northern latitude , and below the equator - south latitude. Lines with degrees of latitude are called parallels, since they run parallel to the Equator and are parallel to each other. If parallels are measured in kilometers, then the lengths of different parallels will be different - they increase as they approach the equator and decrease towards the poles. All points of the same parallel have the same latitude, but different longitude (longitude is described below). The distance between two parallels that differ by 1° is 111.11 km. On the globe, as well as on many maps, the distance (interval) from one latitude to another latitude is usually 15° (this is approximately 1,666 km). In Figure 1, the interval is 10° (this is approximately 1,111 km). The equator is the longest parallel, its length is 40,075.7 km.

The points of intersection of the earth's axis with the surface of the globe are called poles (North and South). The Earth makes one revolution around this axis in 24 hours.

A circle is drawn at the same distance from the poles, which is called the equator.

Parallel - lines conventionally drawn along the surface of the Earth parallel to the equator. The parallels on the map and globe are directed to the west and east. They are not equal in length. The longest parallel is the equator. The equator is an imaginary line on the earth's surface, obtained by mentally dissecting the ellipsoid into two equal parts (Northern and Southern Hemisphere). With such a dissection, all points of the equator turn out to be equidistant from the poles. The plane of the equator is perpendicular to the Earth's axis of rotation and passes through its center. There are 180 meridians on Earth, 90 of them north of the equator, 90 to the south.

The parallels of 23.5° north and south latitude are called tropical circles or simply the tropics. On each of them once a year noon sun happens at the zenith, i.e. sun rays fall vertically.

The parallels of 66.5° north and south latitude are called the polar circles.

Circles are drawn through the North and South poles, meridians are the shortest lines conventionally drawn on the surface of the Earth from one pole to another.

The prime or prime meridian is drawn at the Greenwich Observatory (London, UK). All meridians have the same length and semicircular shape. There are 360 meridians on Earth, 180 to the west of the zero, 180 to the east. The meridians on the map and globe are directed from north to south.

For precise definition the location of any object on the surface of the earth, the equator line alone is not enough. Therefore, the hemispheres are mentally separated by many more planes parallel to the plane of the equator - these are parallels. All of them, like the equatorial plane, are perpendicular to the axis of rotation of the planet. You can draw as many parallels as you like, but usually they are made with an interval of 10-20°. The parallels are always oriented from west to east. The circumference of the parallels decreases from the equator to the poles. At the equator it is greatest, and at the poles it is zero:

Length of parallel arcs

Parallels	Length 1° in km

When the globe is crossed by imaginary planes passing through the Earth’s axis perpendicular to the equatorial plane, great circles are formed - meridians. Translated into Russian, the word “meridian” means “noon line.” Indeed, their direction coincides with the direction of the shadow from objects at noon. If you keep walking in the direction of this shadow, you will definitely come to the North Pole. Meridians – shortest line, conventionally drawn from one pole to the other. All meridians are semicircles. They can be drawn through any points on the surface of the Earth. They all intersect at the pole points. The meridians are oriented from north to south. Average length arc 1° meridian is calculated as follows:

40,008.5 km: 360° = 111 km

The length of all meridians is the same. The direction of the local meridian at any point can be determined at noon by the shadow of any object. In the Northern Hemisphere, the end of the shadow always points north, in the Southern Hemisphere it always points south.

The image of lines of meridians and parallels on the globe and geographical maps is called a degree grid.

Geographic latitude is the distance of any point on the earth's surface north or south of the equator, expressed in degrees. Latitude is northern (if the point is located north of the equator) and southern (if south of it).

Geographic longitude is the distance of any point on the earth's surface from the prime meridian, expressed in degrees. To the east of the prime meridian there will be eastern longitude (abbreviated: E.L.), to the west - western longitude (W.L.).

Geographic coordinates - geographic latitude and geographic longitude of a given object.

LATITUDES AND MERIDIANS

Almost everyone is familiar with the "mysterious lines" on maps and globes that represent latitude (parallels) and longitude (meridians). They form a grid system of coordinates by which any place on Earth can be precisely located - and there is nothing mysterious or difficult about it. Latitude and longitude are coordinates that determine the position of points on the Earth's surface.

Two places on Earth are determined by its rotation around its own axis - the North and South Poles. On globes, the axis is the rod. The North Pole is located in the middle of the Arctic Ocean, which is covered with sea ice, and explorers in the old days reached this pole by sled with dogs (the North Pole is officially believed to have been discovered in 1909 by the American Robert Perry).

However, since the ice moves slowly, the North Pole is not an actual object, but a mathematical one. The South Pole, on the other side of the planet, has a permanent physical location on the continent of Antarctica, which was also discovered by land explorers (a Norwegian expedition led by Roald Amundsen in 1911). Today both poles can be easily reached by plane.

Halfway between the poles at the “waist” of the Earth there is a large circle, which is represented on the globe as a seam: the junction of the northern and southern hemispheres; This circle is called the equator. It is a circle of latitude with a value of zero (0°).

Parallel to the equator, above and below it, there are other circles - these are other latitudes of the Earth. Each latitude has a numerical value, and the scale of these values is measured not in kilometers, but in degrees north and south from the equator to the poles. The poles have the following values: North +90°, and South -90°.

Latitudes located above the equator are called northern latitude, and below the equator - southern latitude. Lines of latitude are sometimes called parallels because they run parallel to the Equator. If parallels are measured in kilometers, then the lengths of different parallels will be different - they increase when approaching the equator and decrease towards the poles.

All points of the same parallel have the same latitude, but different longitude (longitude is described below). The distance between two parallels that differ by 1° is 111.11 km. On the globe, as well as on many maps, the distance (interval) from one latitude to another latitude is usually 15° (this is approximately 1,666 km). In Figure 1, the interval is 10° (this is approximately 1,111 km). The equator is the longest parallel, its length is 40,075.7 km.

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However, in order to accurately determine any place on the globe, it is not enough to know its position relative to north and south; you also need to know the value relative to west and east. Lines of longitude are used for this. Since there are neither western nor eastern poles, it was decided that the line of zero longitude passes through the Greenwich Laboratory, located in England on the eastern outskirts of London.

Lines of longitude are called meridians (Figure No. 2). All of them run perpendicular to the equator and intersect each other at two points on the North and South Poles. To the east of the prime meridian there is an area of eastern longitudes, to the west - western longitudes. Eastern longitudes are considered to be positive, western longitudes are considered negative.

The meridian passing through Greenwich is called the prime meridian (or sometimes the Greenwich meridian). Longitude is measured in degrees. The meeting of eastern and western lines of longitude occurs at Pacific Ocean on the date line. All lines of longitude intersect at the poles, and at these places there is no longitude. One degree of longitude does not mean any fixed distance: at the equator, a longitude difference of 1 degree is equal to 111.11 km, and closer to the poles it approaches zero.

The lengths of all meridians from pole to pole are equal - 20,003.93 km. All points on the same meridian have the same longitude but different latitude. On a globe, as well as on many maps, the distance (interval) from a longitude to another longitude is usually 15°.

Globe is a model of the globe. It clearly shows how the oceans, continents and others are located geographical features. The globe maintains the same scale in all directions, and therefore the image is more accurate than on a map.

The scale must be indicated on a globe or map. It shows the degree to which the sizes of objects and the distances between them are reduced in comparison with the true sizes and distances on the ground. For example, a scale of 1:50,000,000 (one part of fifty million) means that the reduction is 50 million times, that is, 1 cm on a globe or map corresponds to 500 km on the ground.

But globes have a major drawback: they are always on a small scale. If we wanted to make a globe the same size as physical map(1: 5000 000, that is, 1 cm - 50 km), then its diameter would be almost 2.5 m. It is inconvenient to use such a globe.

1. Modern globe. 2. Examples of scales. 3. The surface of the globe, cut into strips along the meridians: distortions are inevitable on a map compiled in this way.

Distances on the globe are determined using a flexible ruler, strip of paper or thread.

On ordinary school globes it is impossible to depict small details in the outlines of continents, in the structure of river networks, mountain ranges, etc. Many states (for example, Denmark, Belgium, Portugal) are depicted with such small figures that there is barely enough space for one circle - symbol capitals. Therefore, they are created geographical maps, on which part of the earth's surface is depicted on a larger scale than on the globe.

If you look at the globe, you can see many thin lines on it. Some go from top to bottom from North Pole to the South and are called meridians. On the globe and maps they indicate the direction of north and south. Other lines perpendicular to the meridians seem to encircle globe. These are parallels. On maps and the globe they are used to determine the direction to the west and east. The parallels are not equal in length. The longest parallel is the equator, the shortest are located near the poles.

1-2. Meridians and parallels are conventional lines on the globe and map. 3. Degree network. 4. Determination of the directions “north - south” along the meridian. 5. Determination of the directions “west - east” along the parallel.

Both parallels and meridians are conventional lines. They are needed in order to determine the location of geographic objects by geographic coordinates.

Questions and tasks

What is a globe?
How is it different from a map? Find in the text of the paragraph the answer to the question: what is the main advantage of a globe compared to a geographic map?
What is the purpose of indicating scale on a globe and map?
Why are parallels and meridians needed?
Explain the geographical meaning of the word "orientate".
Have you ever wondered what geographical object is located in another hemisphere in a place diametrically opposite to where your city is located? Find it on the globe and describe it according to the plan:
1. what he is;
2. what is it called;
3. where it is located: in what climatic and time zones it is located, what geographical objects are nearby.
Find the intersection of the equator and the prime meridian.
Select from the list characteristic features parallels:
1. have the shape of a circle;
2. carried from pole to pole;
3. they determine the direction “west - east”;
4. all the same length.