What are parallels and meridians? Degree network, its elements. Geographical coordinates - Knowledge Hypermarket

This video tutorial will be especially useful for those who want to independently get acquainted with the topic "Degree grid". During the lesson, you will be able to define what a parallel, meridian and degree grid are. The teacher will explain in detail how you can determine the direction of the parallels and meridians on the map.

The direction of the meridian coincides with the direction of the shadow at noon. Meridian- a conditional line drawn on the surface of the Earth from one pole to another. The magnitude of the arc and circumference of the meridian is measured in degrees. All meridians are equal, intersect at the poles, have a north-south direction. The length of one degree of each meridian is 111 km (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 length of the arc along the meridian is 20 degrees. To find out this length in kilometers, you need 20 x 111 = 2220 km.

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

The countdown of the meridians starts from the zero meridian (0 degrees) - Greenwich.

Rice. 2. Meridians on the map of Russia

Parallel- a conditional 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 border of the map.

Length of 1 degree parallels ():

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

Parallels and meridians can be drawn through any place on earth's surface. Parallels and meridians can be used to determine the main and intermediate sides of the horizon. The meridians determine the directions "north", "south", along the parallels - "east", "west". Intersecting, parallels and meridians form a degree network.

Homework

Paragraph 11.

1. Tell us about the grid.

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

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

Materials on the Internet

1. Federal Institute pedagogical measurements ().

2. Russian Geographic Society ().

Meridians and parallels

Meridians and parallels

Meridians and parallels
coordinate lines on a map or globe. Meridians are lines of constant longitude that pass through both poles of the planet and indicate the direction "north - south", and parallels are lines of constant latitude that run parallel to the equator in the direction "west - east". Intersecting, these lines form a grid of geographical coordinates on the map. Usually, integer meridians and parallels are drawn, but for accurate drawing and removal of coordinates, the grid can be thickened to minutes (and on large-scale maps, even to seconds). To do this, the cards have a minute frame, where fractions of degrees are marked. Depending on the method of definition, astronomical, geodesic, geographic and geomagnetic meridians and parallels are distinguished, and on the celestial sphere, respectively, celestial meridians and parallels.

Geography. Modern illustrated encyclopedia. - M.: Rosman. Under the editorship of prof. A. P. Gorkina. 2006 .

See what "meridians and parallels" are in other dictionaries:

Geographic Encyclopedia

Small circles of the sphere, composed by its intersection with a plane parallel to some basic plane (horizon, equator, ecliptic); otherwise a circle, all points of which have equal latitude, declination, or altitude. Daily P. stars small circles, ... ... encyclopedic Dictionary F. Brockhaus and I.A. Efron

- (historical) The initial concept of K. can be found even among savages, especially those living along the banks and about you and having a more or less clear idea of ​​\u200b\u200bthe areas surrounding their territory. Travelers who questioned the Eskimos of S. America and ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

Mappings of the entire surface of the earth's ellipsoid (See Earth's ellipsoid) or any part of it onto a plane, obtained mainly for the purpose of constructing a map. Scale. K. items are built on a certain scale. Reducing mentally ... ... Great Soviet Encyclopedia

An example of a map projection Mercator projection A map projection is a mathematically defined way of displaying the surface of an ellipsoid on a plane. The essence of projections is connected with the fact that the figure of the Earth ... Wikipedia

An example of a map projection Mercator projection A map projection is a mathematically defined way of displaying the surface of an ellipsoid on a plane. The essence of the projections is related to the fact that the figure of the Earth is an ellipsoid that is not deployable in ... ... Wikipedia

Mapping of the entire surface of the earth's ellipsoid or any part of it onto a plane, obtained mainly for the purpose of building a map. K. p. draw on a certain scale. Mentally reducing the earth's ellipsoid to Mraz, one gets its geometric. model ... ... Mathematical Encyclopedia

Meridian(s) meridians and parallels coordinate lines on a map or globe. Meridians are lines of constant longitude that pass through both poles of the planet and indicate the direction "north - south", and parallels are lines of constant latitude that go ... ... Geographic Encyclopedia

Meridians and parallels are coordinate lines on a map or globe. Meridians are lines of constant longitude that pass through both poles of the planet and indicate the direction "north - south", and parallels are lines of constant latitude that run parallel ... ... Geographic Encyclopedia

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We remember: What is called the equator? What is the length of the earth's equator? What points on Earth are called geographic poles?

Keywords:equator, parallels, meridians, prime meridian, hemisphere, degree grid, geographic location.

1. Parallels. Have you already remembered that e c v a t o r- this is a line conventionally drawn on the earth's surface at the same distance from the poles. It divides the globe into Northern and Southern hemispheres (Fig. 42).

Rice. 42. Hemispheres of the Earth. What separates the Western and Eastern, Northern and Southern hemispheres?

Parallels are lines that are conventionally drawn on the surface of the Earth parallel to the equator. The word "parallel" indicates the position of this line relative to the equator: all points of one parallel are at the same distance from the equator. As you can see on the globe in the shape of a parallel - a circle, their length decreases from the equator to the poles. The largest parallel is the equator. A parallel can be drawn through any point on the earth's surface. Each parallel is directed from west to east (Fig. 43).

Rice. 43. Parallels. Rice. 44. Meridians.

Meridians. The shortest lines conventionally drawn on the surface of the Earth from one pole to another are called meridians (Fig. 44). The direction of the meridian at any point on the earth's surface is most simply determined through the direction of the shadow from objects at noon. Therefore, the meridian is also called the noon line (Fig. 46). Translated from Latin into Russian, the word "meridian" means "midday line".

Figure 46. The meridian line coincides with the direction of the shadow from objects at noon.

Meridians indicate the exact direction from north to south. At each point, the meridian is perpendicular to the parallels, which is why they form a right angle (90 °) with each other. Therefore, if you become facing north, that is, in the direction of the meridian, and spread your arms to the sides, they will indicate the direction of the parallel.

Like a parallel, a meridian can be drawn through any point on the earth's surface.

One of the meridians is conditionally considered to be the initial, or zero. According to the international agreement of 1884, the Greenwich meridian passing through the Greenwich Observatory in London is considered the initial one. The initial meridian divides the globe into two hemispheres - Western and Eastern (Fig. 42).

3. Degree grid. On a globe and maps, meridians and parallels are drawn through the same number of degrees. For example, after 10 0 or 15 0 . (Find these symbols on the globe and map). Intersecting, parallels and meridians form a degree grid on the globe and maps (Fig. 45).

Rice. 45. Degree grid.

* On a globe, parallels and meridians intersect at right angles. When these angles on the map are greater or less than a straight line, this indicates distortion of angles and directions, and hence the shape of objects. On the globe, all meridians have the same length, and the length of the parallels decreases from the equator to the poles, which is true. Violation of this on the map indicates a distortion of distances, and, consequently, areas.

1. What is called a parallel? Meridian? Degree grid? 2. What hemispheres does the equator and the prime meridian divide the globe into? What hemisphere is your area in?

3* Copy table 2 in a notebook and fill it out (instead of a question, write down the answer).

Table 2.

Graticule

Practical work.

1. Find any meridian on a globe or on a map of the hemispheres and determine which continents and oceans it crosses from south to north. 2. Show any parallel and determine which continents and oceans it crosses from west to east.

Knowing that our planet has a shape very close to the shape of a ball, and observing during travels in various places the apparent rotation of the Sun and stars, ancient scientists established certain conditional lines for orientation on the earth's surface.

Let's go on a mental journey on the surface of the Earth. The position above the horizon of the imaginary axis of the world, around which the firmament rotates daily, will change for us all the time. In accordance with this, the picture of the movement of the starry sky will also change. Going north, we will see that the stars in the southern part of the sky rise to a lower height each night. And the stars in the northern part - in the lower climax - have a greater height. Moving long enough, we'll hit North Pole. Not a single star rises or falls here at all. It will seem to us that the whole sky is slowly spinning parallel to the horizon.

Ancient travelers did not know that the apparent movement of the stars is a reflection of the rotation of the Earth. And they haven't been to the Pole. But it was necessary to have a reference point on the earth's surface. And they chose for this purpose a north-south line, easily identifiable by the stars. This line is called the meridian.

Meridians can be drawn through any point on the surface of the Earth. Many meridians form a system of imaginary lines connecting the North and South Poles of the Earth, which is convenient to use to determine the location.

Let's take one of the meridians as the initial one. The position of any other meridian in this case will be known if the reference direction is specified and the dihedral angle between the plane of the desired meridian and the plane of the initial meridian is given.

The position of the prime meridian has changed many times over the centuries. In 1493, immediately after the first voyage of Columbus to the shores of the West Indies, Pope Alexander VI divided the real world between Spain and Portugal. The border of the future possessions of the two greatest maritime powers dissected Atlantic Ocean from pole to pole. And when, decades later, it turned out that the contours of the lands of the New World and the distant borders of Asia, it turned out that in the western, "Spanish" half the globe all of America fell, with the exception of its Brazilian ledge, and in addition to Brazil, the entirety of Africa and Asia fell into the eastern, "Portuguese" half.

Such a reference line of longitudes existed for about one hundred and fifty years. In 1634, under Cardinal Richelieu, a special commission of French scholars proposed to draw the prime meridian closer to Europe, but in such a way that the entire territory of Europe and Africa would be east of it. For this purpose, the zero meridian was drawn through the westernmost point of the Old World, the western tip of the westernmost of the archipelago canary islands- Island of Ferro. In 1884, at an astronomical conference in Washington, the reference meridian for the globe was taken to be the one that passes through the axis of one of the telescopes of the Greenwich Observatory. The Greenwich meridian remains the prime meridian to this day.

The angle formed by any meridian with the initial is called longitude. Longitude, for example, the meridian of Moscow 37? east of Greenwich.

To distinguish points lying on the same meridian from each other, it was necessary to introduce a second geographical coordinate - latitude. Latitude is the angle drawn in this place Earth's surface a plumb line forms with the plane of the equator.

The terms "longitude" and "latitude" have come down to us from ancient navigators who described the length and width mediterranean sea. The coordinate that corresponded to the measurements of the length of the Mediterranean Sea became longitude, and the one that corresponded to the width became the modern latitude.

Finding latitude, like determining the direction of the meridian, is closely related to the movement of stars. Already ancient astronomers proved that the height of the celestial pole above the horizon is equal to the latitude of the place.

Let's assume that the Earth has the shape of a regular ball, and cut it along one of the meridians, as shown in the figure. Let the person shown in the figure as a light figure stand at the North Pole. For him, the direction is up, i.e. the direction of the plumb line coincides with the axis of the world. The pole of the world is right above his head. The height of the celestial pole is here 90?.

Since the apparent rotation of stars around the axis of the world is a reflection of the real rotation of the Earth, then at any point on the Earth, as we already know, the direction of the axis of the world remains parallel to the direction of the axis of rotation of the Earth. The direction of the plumb line changes when moving from point to point.

Take, for example, another person. The direction of the axis of the world remained the same for him as for the first one. And the direction of the plumb line has changed. Therefore, the height of the celestial pole above the horizon here is not 90?, but much less.

From simple geometric considerations it is clear that the height of the celestial pole above the horizon is indeed equal to the latitude.

A line connecting points of equal latitude is called a parallel.

Meridians and parallels form the so-called system of geographical coordinates. Every point on the earth's surface has a well-defined longitude and latitude. And vice versa, if the meal and longitude are known, then one parallel and one meridian can be built, at the intersection of which one single point will be obtained.

If our planet is “cut” through the axis of rotation and perpendicular to it by many planes, then vertical and horizontal circles will appear on the surface - meridians and parallels.


The meridians will converge at their ends at two points - at the North and South Poles. Parallels, as the name implies, are parallel to each other. Meridians are used to measure longitude, parallels - latitude.

Such a simple action at a superficial glance - the "line" of the Earth - has become greatest discovery in planetary exploration. It made it possible to use coordinates and accurately describe the location of any object. Without parallels and meridians, it is impossible to imagine any map, not a single globe. And they came up with ... in the III century BC, the Alexandrian scientist Eratosthenes.

Reference. Eratosthenes possessed encyclopedic knowledge for those times in all areas. He was in charge of the legendary Library of Alexandria, wrote the work "Geography" and became the founder of geography as a science, compiled the first map of the world and covered it with a degree grid of verticals and horizontals - he invented a coordinate system. He also introduced the names for the lines - parallel and meridian.

Meridian

A meridian in geography is called a half line of a section of the earth's surface, drawn through and any point on the surface. All imaginary meridians, of which there can be an infinite number, are connected at the poles - North and South. The length of each of them is 20,004,276 meters.

Although you can mentally draw as many meridians as you like, for the convenience of movement, mapping their number, their location was streamlined by international treaties. In 1884, at the International Meridian Conference in Washington, it was decided that the initial meridian (zero) would be the one that passes through Greenwich, a district in southeast London.

However, not everyone immediately agreed with this decision. For example, in Russia, even after 1884 until the beginning of the 20th century, the zero meridian was considered to be its own - Pulkovo: it "passes" through the Round Hall of the Pulkovo Observatory.

Prime Meridian

The zero meridian is the reference point of geographic longitude. He, respectively, has a zero longitude. This was before the creation of the world's first satellite navigation system Transit.


With its appearance, the prime meridian had to be slightly shifted - 5.3 "relative to Greenwich Mean. This is how the International Reference Meridian appeared, which is used as a longitude reference point by the International Earth Rotation Service.

Parallel

Parallels in geography are called lines of an imaginary section of the surface of the planet by planes that are parallel to the equatorial plane. The parallels depicted on the globe are circles parallel to the equator. They are used to measure latitude.

By analogy with the Greenwich zero meridian, there is also a zero parallel - this is the equator, one of the 5 main parallels that divides the Earth into hemispheres - southern and northern. Other main parallels are the tropics North and South, the polar circles - North and South.

Equator

The longest parallel is the equator - 40,075,696 m. The rotation speed of our planet at the equator is 465 m / s - this is much more than the speed of sound in the air - 331 m / s.

Southern and Northern tropics

The Tropic of South, also called the Tropic of Capricorn, lies south of the equator and represents the latitude over which the midday sun is at its zenith on the winter solstice.

The Tropic of the North, also known as the Tropic of Cancer, is located north of the Equator and, like the Tropic of the South, represents the latitude over which the midday sun is at its zenith on the day summer solstice.

Arctic Circle and Antarctic Circle

The Arctic Circle is the boundary of the polar day region. To the north of it, in any place at least once a year, the sun is visible above the horizon 24 hours a day, or the same amount is not visible.

The southern polar circle is similar in everything to the northern one, only it is located in the southern hemisphere.

Graticule

The intersections of meridians and parallels form a degree grid. Meridians and parallels are spaced at intervals of 10° - 20°, smaller divisions, as in the corners, are called minutes and seconds.


With the help of a degree grid, we determine the exact location of geographical objects - their geographical coordinates, calculating longitude by meridians, and latitude by parallels.