What is the difference between meridians from. Degree network, its elements

What lines did the meridians and parallels on the globe carried out?

1. Lines of meridians and parallels on various maps. On the world map, compiled by combining the globe strips along the equator, meridians are equal in size straight lines. Parallels carried out perpendicular to them, also straight lines. Their length from the equator to the poles is not shortened, as on the globe, but remains the same. (What does this say about?)
Equator and medium meridian of each hemisphere on the hemispheus map are shown by straight lines. Other meridians and parallels are curved lines of different lengths. From the average meridian to the edges of the length of meridians increases. (What does this say about?)
On the map of Kazakhstan, parallels are depicted in the form of circumference arcs. Meridians are represented by the straight lines approaching the top.
The map is indicated by longitude and latitude. On the map, the hemisphere longitude is shown at the intersection points of meridians with the equator.
Meridians and parallels on the globe and maps are carried out through same number degrees (determine how many degrees they are shown on the globe, a map of the hemispheres and the map of Kazakhstan). Therefore, grids formed from changing the lines of meridians and parallels are called degree grids.

2. Using lines of meridians and parallels it is very easy to determine the geographical coordinates on the map. To do this, you first need to find out, between what parallels of the latitude and meridians of longitude is the desired point. For example, the point is between 40 ° and 45 ° of northern latitude, 70 ° and 75 ° East longitude (Fig. 32). To determine more accurately breadth on the map Using the ruler, measure the distance (AB) between two parallels, as well as the distance between the bottom parallel and the point N (AN). On the map of the cut AU equal to 5 °.

Fig. 32. Determination of the point of coordinates.

By distance An. In degrees add 40 °. If instead An.we would measure HV and this distance in degrees take away from 45 °, then the same result will still get.
Longitude on the map is determined by the same method. Measure the segments of the SD and CH ruler.

To the obtained value in degrees add 70 ° and we obtain the longitude of the point of N. Just as when determining the latitude line, instead of a segment SN You can measure the cut DN. Then from 75 ° taking the value obtained.

Fig. 33. Parts of degree grids on various maps.

1. Figure 33, determine which cards do each degree mesh belong?

2. Find a semisphan point on the map indicating only one of the coordinates.

3. On the map of Kazakhstan, determine approximately the geographical coordinates of your area.

The intersection points of the earth's axis with the surface globe Called poles (Northern and South). Around this axis, the land in 24 hours makes one turn.

At the same distance from the poles, a circle was carried out, which is called the equator.

Parallel - lines, conditionally spent on the surface of the Earth parallel to the equator. Parallels on the map and the globe are directed to the West and East. They are not equal to each other in length. The longest parallel is the equator. Equator - imaginary line on the earth's surface, obtained with the mental dissection of the ellipsoid into two equal parts (Northern and South Hemisphere). With such dissection, all equator points are equivalent from poles. The plane of the equator is perpendicular to the axis of rotation of the Earth and passes through its center. A total of 180 meridians, 90 of them north of Equator, 90 - south.

Parallels 23.5 ° North and South latitude are called tropical circles or just tropics. At each of them, once a year, the midday sun happens in Zenith, that is, the sun's rays are falling.

Parallels 66.5 ° North and South latitude are called polar circles.

Through the North and South Poles, circles were held, meridians - the shortest lines, conditionally spent on the surface of the Earth from one pole to another.

The initial or zero meridian was held at the Greenwich Observatory (London, United Kingdom). All meridians have the same length and shape of semi-resources. A total of 360 meridians, 180 west of zero, 180 - east. Meridians on a map and globe are directed from north to south.

For accurate definition The locations of any object on the surface of the Earth of one equator line is not enough. Therefore, the hemisphere is mentally separated by another set of planes, parallel planes of the equator - these are parallels. All of them, as well as the plane of the equator, perpendicular to the axis of rotation of the planet. Parallels can be carried out as much as possible, but they are usually carried out with an interval of 10-20 °. Parallels are always oriented from west to east. The length of the circle of parallel decreases from the equator to the poles. At the equator, it is the largest, and on the poles is zero:

Length arc parallel

When crossing the globe, imaginary planes passing through the Earth axis perpendicular to the equator plane, large circles are formed - meridians. Translated into Russian, the word "meridian" means "midday line". Indeed, their direction coincides with the direction of the shade of items at noon. If you go all the time towards this shadow, you will definitely come to the North Pole. Meridians - the shortest line, conditionally spent from one pole to another. All meridians are semiwesight. They can be carried out through any points on the ground surface. All of them intersect at the points of the poles. Meridians are oriented from north to south. Medium length Arcs 1 ° Meridian is calculated so:

40 008.5 km: 360 ° \u003d 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 shadow from any item. In the northern hemisphere, the end of the shadow always shows the direction to the north, in South - south.

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

The geographical latitude is the distance of any point of the earth's surface to the north or south of the equator, expressed in degrees. The latitude is North (if the point is located north of the equator) and southern (if south of it).

Geographical longitude is the distance of any point of the earth's surface from the initial meridian, expressed in degrees. Eastern longitude will be east of the zero meridian (abbreviated: in. D.), To the West - Western (z. D.).

Geographical coordinates - Geographic latitude and geographical longitude of the specified object.

If our planet through the axis of rotation and perpendicular to it "inhabitants" with a plurality of planes, then the surface will appear vertical and horizontal circles - meridians and parallels.


Meridians will comply with their ends at two points - in the North and South Poles. Parallels, as follows from the name, are parallel to each other. Meridians serve to measure longitude, parallels - latitude.

Such a simple look at a superficial view - "Rollover" of the Earth - became the greatest discovery In the planning of the planet. It made it possible to use the coordinates and accurately describe the location of any object. Without parallels and meridians, it is impossible to submit any card or a single globe. And invented them ... In the III century BC, Alexandrian scientist Eratosthen.

Reference. Eratosthenes possessed encyclopedic in the time knowledge in all areas. He headed the legendary Alexandria library, wrote the work of "geographic" and became a heproxpecker of geography as science, was the first world map and covered it with a degree grid of verticals and horizontals - invented the coordinate system. He also introduced for the name lines - parallel and meridian.

Meridian

Meridian in geography is called half the cross section of the earth's surface, conducted through and any point on the surface. All imaginary meridians, which can be an infinite amount, are connected on the poles - North and South. The length of each of them is 20,004,226 meters.

Although Meridians mentally, you can spend somehow a lot, for the convenience of movement, mapping their number, the location was ordered 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 - District in the south-east of London.

However, not everyone immediately agreed with such a decision. For example, in Russia, even after 1884, until the beginning of the twentieth century, Zero Meridian was considered their own - Pulkovsky: he "passes" through the Round Hall of the Pulkovo Observatory.

Prime Meridian

Zero meridian call the point of reference of the geographical longitude. He himself, respectively, has a zero longitude. So it was before creating the world's first satellite transit navigation system.


With its appearance, Zero Meridian had a little - at 5.3 "relative to Greenwich - to move. So the international support meridian appeared, which uses as a point of the length of the longitude of the International Earth Rotation District.

Parallel

Parallels in geography are called the lines of the imaginary cross section of the surface of the planet with planes, which are parallel to the equatorial plane. The parallels depicted on the globe are circles parallel to the equator. With their help measure geographic latitude.

By analogy with Greenwich Zero Meridian there is a zero parallel - this is the equator, one of the 5 main parallels, which divides the land on the hemisphere - South and North. Other major parallels - Tropics North and South, Polar Circles - North and South.

Equator

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

South and Northern Tropics

The southern tropic, which is also called the tropic of Capricorn, is south of the equator and is a breadth of which half-day sun stands in Zenith on the day of the winter solstice.

Northern tropic, he is the tropic of cancer, located north of the equator and, similarly to the southern treropic, represents breadth, over which half-day sun stands in Zenith on the day of summer solstice.

Northern polar circle and southern polar circle

The north polar circle is the border of the Polar Day. North of him in any place at least once a year the sun can be seen above the horizon 24 hours a day or the same is not visible.

The southern polar circle in everything is similar to the North, only located in the southern hemisphere.

Degree grid

The intersections of meridians and parallels form a degree grid. Meridians and parallels are located with an interval of 10 ° - 20 °, smaller divisions, as in the corners, are called minutes and seconds.


Via degree grid We define the exact location of geographic objects - their geographical coordinates, calculating the longitude in the meridians, and in parallel - breadth.

"And the cities and countries, parallels, meridians smell," in the song called "Globus". But if the city and countries designated on the globe also exist in reality, then parallels and meridians are the essence of the objects imaginary, applied to the globe or map exclusively for the convenience of reading and orientation.

The best orienteer assistant is the coordinate system, which must have a reference point. In the earth (however, the same principle can be applied to any other planet or its satellite - it would be, for what) such an imaginary "zero point" was determined with the help of poles - points through which the axis of its rotation passes. The North Pole - the object is more mathematical, it is in the Northern Arctic Ocean, but the South Pole is a completely real point on land, on the mainland called Antarctica, you can get there, you can take a picture there - if you are not afraid to freeze, of course ...

So, at an equal distance from these very poles, in the middle between them, there is an imaginary "belt" of the Earth, dividing the planet in half, to the Northern and South Hemisphere. Most continents are in some one of them, and only Africa is in both. So, the equator is - this is the "point of reference", which is considered zero bread. Imaginary lines conducted on the map and the globe parallel to the equator are called parallels.

The latitude is measured in degrees, 1 degree - approximately 111 km. Consider it from the equator (the farther from him more Number: Equator - 0 degrees, poles - 90 degrees). North of the Equator are counted degrees of northern latitude, to the south-east longitude. There is another way of designation: South of the Equator, the latitude is recorded with a minus sign (this can be understood: those who created geographic science, lived in the northern hemisphere, and their own shirt, as you know, closer to the body).

All this, of course, is wonderful, but ...

Recall the Roman Zhevna "Children of Captain Grant." The heroes who sent to the rescue captain a grant and his companions who survived after the shipwreck were known that the place of their location is thirty-seven degrees eleven minutes of southern latitude. To find them, the heroes had to take a world journey along this parallel.

In order to avoid such difficulties, there is a second coordinate - longitude, and on the map it is denoted by meridians - lines connecting the poles.

If we wanted to choose a parallel for the longest around the world travelThat would be undoubtedly the equator. But to choose for this case, the meridian will not work - they are about the same, so choosing among them the point of reference is not so simple, so for a long time In this regard, there was a disaster: in France, Paris Meridian took the point of reference, in Russia - passing through the Pulkovo observatory, etc. Finally, in 1884, at the International Conference in Washington, a single point of reference was taken in Washington, passing through the axis of the Observatory of the Observatory in Greenwich - the administrative district of London on the right bank of the Thames. It is from Greenwich Meridian that the Western and Eastern Longitude is considered (the heroes of the novel mentioned are not lucky: the longitude in the note was washed with water).

The number of kilometers in one degree longitude is more complicated than as applied to the latitude: it is not an alternative on different latitudes - at the equator, too 11 km, and the closer to the poles - the less).