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 determination, astronomical, geodetic, geographic and geomagnetic meridians and parallels are distinguished, and on celestial sphere, respectively, are 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) Initial concept about K. can be found even among savages, especially those who live along the coast and about you and who have 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
Map projection example Mercator projection Map projection mathematically certain way 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
Books
- Grebenshchikov Boris Borisovich. Few rock musicians have not only reached the heights of fame, but also studied everything related to the work of their predecessors and colleagues so thoroughly. Since 2005, Boris Grebenshchikov has been leading ...
Globe and geographic Maps"entangled" in a kind of grid consisting of intersecting lines. These lines did not appear on the maps immediately, since in ancient times the maps resembled the simplest plans.
The globe and the planes of its section
The earth is a sphere slightly flattened at the poles. The sphere can be cut by planes along different directions. It can be cut, firstly, in the same way as an orange is divided into slices, and, secondly, in the same way as an orange is cut across the slices with a knife. With any method of dissecting the ball by planes, circles are obtained, the boundaries of which are circles. The diameter of the circles is greatest if the section planes pass through the center of the ball. The diameters of such circles are equal to the diameter of the sphere.
Let's turn to and mentally dissect Earth planes perpendicular to the Earth's axis of rotation. Circles parallel to each other appear on the surface of the globe. These circles are called parallels (from Greek word parallclos - walking beside). The longest and main parallel is the equator, its length is 40,076 kilometers.
The equator is on equal distance from the poles of the planet and divides the Earth into the North and southern hemisphere. The length of other parallels decreases in the direction from the equator to the south and to the north. All points lying on the same parallel are equally distant from the equator. The lines of parallels show the west-east direction.
If you cut the globe with planes that pass through the axis of rotation of the Earth, then meridians will appear on the surface of the globe - semicircles connecting the North and south poles Earth. They are perpendicular to the parallels and show the north-south direction. The word "meridian" itself means "midday" (from the Latin word meridianus), since the direction of all meridians coincides with the direction of the shadow from objects at noon.
All meridians have the same length - 20,005 kilometers. By agreement between the countries, the main, initial meridian is considered to be the meridian passing through the Greenwich Observatory in the suburbs of London. Therefore, this meridian is also called the Greenwich meridian. Greenwich meridian and its continuation on the opposite side
of the globe divide the Earth into Western and Eastern hemispheres.
Parallels and meridians on maps
The parallels on the globe are circles, and the meridians are semicircles. But due to distortions, when the convex surface of the Earth is transferred to a plane, the image of these lines looks different. Whatever the form of the parallels and meridians, on any map, the directions to the east and west are determined only by the direction of the parallels, and to the north and south - only by the direction of the meridians. Thus, parallels and meridians allow you to navigate, that is, determine directions to the sides of the horizon.
Lines of parallels and meridians on the globe and maps can be drawn as many as you like. But only one meridian and one parallel passes through one point of the surface. The position of any point on a flat sheet can be characterized by two numbers of coordinates that show the position of this point relative to the edges of the sheet.
On a spherical surface, the coordinates of points are determined with respect to the equator and prime meridian. To do this, use the system of parallels and meridians.
Today, our associations associated with travel have changed a lot. "Unlucky Notes", "Eagle and Tails" against the backdrop of the cheapness of All Inclusive compared to the Soviet ones did their job. Does anyone now remember about "parallels, meridians"? Well, at least a song, right?
Okay, let's remember. Only cities and countries will not flicker - surprisingly, but the parallels with the meridians and next to us pass :)
Have you guessed what we're talking about yet? ;)
Then let's start from afar.
As a child, I had a globe on my desk. How to read Jules Verne without a globe?!
And now the hand does not rise to buy this invention - more a luxury item. And, as it were, irrelevant in the age of Google maps and Yandex satellite.
But I'm not talking about the globe. The journey in search of Captain Grant made the imaginary lines on the globe real, almost tangible. Man's addiction to imaginary lines is quite understandable, because they symbolize the elusive mystery of Being. Again, pirate maps, treasures and adventures. All thirty-three pleasures. Just the silhouette of a steering wheel or the ringing of a ship's bell already triggers the imagination and makes our hearts beat! This is not a booking with a choice between BB, HB and AI.
But the Caribbean is too far away, the pirates are too long ago, and all this, connected together by the movie business, turns into a fantasy, killing a very real romance. distant wanderings. And if you are asked what parallel Cheboksary stands on, some will be surprised: "Well, do we have parallels?"
And when they find out that the 56th parallel runs a little to the south, they will say in disappointment: "Ah, well, I thought so, where can we ...".
Well, here it is, the 56th parallel, here, look. Precisely 56° northern latitude(We are used to integer values, but nature doesn’t care about them, just like city planners!):
Panorama from DCP 56°N 47°E (click to view full size)
There are people for whom the awl still works, and even too much - and they invent "home" parallels with the meridians (known to some as the Hartman grid), which pass every two meters, and even teach how to properly position the bed in order to don't hit the nodes. It takes a psychic to find these lines and knots. But it's not scary, even I can do it, and even without a frame :). And everyone can, if they try.
Only here is the incident: it is customary to take the distance between the lines the same everywhere. I have never heard that the grid of Hartman and Murmansk differed from the grid, for example, in Odessa! ;) Apparently, psychics, even graduates, do not always remember the features of the geometry of the sphere. Meanwhile, you can stretch a square grid of figs onto a globe!
But let's leave the glitches of psychics aside and return to geography.
With the equator and with all the meridians it is easier: one degree when moving along them is the same everywhere and is approximately 40000/360=111 km. And one minute of arc, respectively, is 60 times less: 1.852 km.
By the way, who knows what this number is? My friends, this is nautical mile! Have you heard of such a unit of distance?
So, with latitude, everything is clear. To get one degree north or south, you have to walk 111 km.
And how many from one meridian to another? At the equator - the same 111 km. And at the pole, obviously, zero! Because there all the meridians converge. And you can commit trip around the world" around the pole, while crossing all time zones in a few steps!
At our latitude from one meridian to another - only 62 kilometers with a tail.
Therefore, the mysterious points of intersection of parallels and meridians are not so far from us.
And these nodes are beautifully called: confluent points.
Immediately there is a desire to find them and visit. Why, ask? Well, you're not original. Vysotsky has already managed to ask you:
I asked you: "Why are you going uphill? -
And you went to the top, and you rushed into battle. -
After all, Elbrus can be seen great from an airplane ... "
You laughed and took it with you.
We went too. Will strange people ready to travel virtual lines and their intersections, and was born international project Degree Confluence Project:
Briefly, I already wrote about those points that are located on the territory of Chuvashia (there are only three of them), c.
I visited one of them as soon as I bought a communicator with GPS. This closest point to us with coordinates 57°N 47°E is located near the village of Ishley, on the other side of the village of Khachiki. You can drive close to the point by car both through Ishley and through Khachiki:
A panorama from the point is given above, and a visit to the point is described on the DCP website.
We see that there are still many white spots on the territory of Russia (points not visited by DCP users). This does not mean that no one has ever been there, it just means that no one, even if they knew the coordinates, bothered to tell about it on the DCP project :)
Surprisingly, the lion's share of points in the European part of Russia was "discovered" by the same traveler - Vladimir Chernorutsky. Today he has 131 visited points in 5 countries!
And I must say that the points can be in the most remote and inaccessible places - taiga, swamps, and even in the middle of a lake or river. AT last case enthusiasts specially take an inflatable boat with them and pick up in Right place already on the water! The nearest water point is on the Volga near Zvenigovo:
While searching for my first confluence point, I did not know anything about the Degree Confluence Project, and I safely forgot the note I read about it on Habré. But after visiting I remembered, and easily found the appropriate site. It turned out that at this point I was only the third visitor.
But, to my great surprise, on the map of Russia I found a hitherto undiscovered point N57° E47° in Kirov region, only 180 km from my house! Well, seven miles is not a detour, as they say.
Just like , I am extremely lucky. I managed to become the discoverer of the point, ahead of the competitor by literally three days!
It took a long time to arrive, I was almost late. I chose a relatively free day, and drove along the route Cheboksary - Yoshkar-Ola - Sanchursk and another 16 km, through the village with beautiful name Smetanino (almost visiting Uncle Fyodor with Matroskin;)). Unfortunately, the last 35 km of the road (before and after Sanchursk) turned out to be a real off-road rally, suitable only for 4x4 lovers, since only memories and asphalt pits remained from the road. This segment of the journey took almost two hours! Fortunately, now the road has been repaired there, so you can drive without fear:
I had to leave the car at the nearest point on the road and walk about two kilometers through a swampy, abandoned field to a forest visible on the horizon, where the intersection point is located:
The point itself is located in the forest, fortunately not very far:
Don't forget your mosquito gear if you want to visit this place in summer! I was never able to shoot the planned panorama; hands and face were black under a layer of mosquitoes and horseflies. And here is the point. In the picture at the beginning of the post, you see a mosquito climbing into the lens, and a communicator spattered with fresh blood. So it goes! But we got:
Like these ones geographical travel, such discoveries. It would seem that interesting? Taiga, horseflies - romance! :)
There were no more undiscovered points nearby, except in the wilds of the Kirov region and no closer than 300-400 km.
But it is not necessary to climb into the taiga far away.
It would be possible to organize tourism in the nearest points, why not? It's time to revive the romance!
By the way, one of my colleagues from Togliatti, even before the era of GPS, carefully studied maps and found out that the middle of the Volga is located near Cheboksary!
Hey city officials! Instead of constructing pathos monuments with outstretched arms and marking the “zero mile” for tourists on Red Square, it would be better to mark the middle of the Volga. And then you tell where you are from, and you have to clarify that Cheboksary is not where pasties and Cheburashka are, but between Gorky and Kazan. But now you can proudly declare: right in the center of the Volga!
Big and small trips(cm.
Globe is a model of the earth. It clearly shows how the oceans, continents and others are located. geographic features. On the globe, the same scale is maintained in all directions, and therefore the image is obtained more accurately than on the map.
A scale must be indicated on a globe or map. It shows the degree of reduction in the size of objects and the distances between them compared to true size and distances on the ground. For example, a scale of 1:50,000,000 (one fifty-millionth) 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: 5,000,000, that is, 50 km in 1 cm), 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: on a map drawn up in this way, distortions are inevitable.
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 the continents, in the structure of the river network, mountain ranges, etc. Many states (for example, Denmark, Belgium, Portugal) are depicted in such small figures that they barely have enough space for one circle - symbol capital Cities. Therefore, geographical maps are created, on which a part of the earth's surface is depicted on a larger scale than on a globe.
If you look at the globe, you can see a lot of thin lines on it. Some go from top to bottom North Pole to the South and are called meridians. On the globe and maps, they indicate the direction to the north and south. Other lines, perpendicular to the meridians, encircle the globe, as it were. These are parallels. On maps and the globe, they 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 - conditional 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 conditional lines. They are needed in order to determine the location geographical 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 geographical map?
- What is the purpose of scale on a globe and map?
- What are parallels and meridians for?
- Explain the geographical meaning of the word "orient".
- Have you ever thought about what geographical object is located in the other hemisphere in a place diametrically opposite to where your city is located? Find it on the globe and describe according to the plan:
- what he really is;
- what is the name of;
- where it is located: in what climatic and time zones it is located, what geographical objects are in the neighborhood.
- Find the intersection of the equator and prime meridian.
- Select from the list character traits parallels:
- have the shape of a circle;
- carried out from pole to pole;
- they determine the direction "west - east";
- all the same length.
In the form of what lines are the meridians and parallels drawn on the globe?
1. Lines of meridians and parallels on various maps. On a map of the world, compiled by combining the strips of the globe along the equator, the meridians are straight lines of equal size. Parallels drawn perpendicular to them are 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?)
The equator and the median meridian of each hemisphere are shown as straight lines on the map of the hemispheres. Other meridians and parallels - curved lines different lengths. From the middle meridian to the edges, the length of the meridians increases. (What does this say?)
On the map of Kazakhstan, the parallels are shown as arcs of circles. The meridians are represented by straight lines approaching the top of the map.
The map frame has longitude and latitude. On the map of the hemispheres, longitude is shown at the points of intersection of the meridians with the equator.
Meridians and parallels on the globe and maps pass through the same number degrees (determine how many degrees they are shown on the globe, the map of the hemispheres and the map of Kazakhstan). Therefore, grids formed by changing the lines of meridians and parallels are called degree grids.
2. With the help of meridian lines and parallels, it is very easy to determine geographical coordinates on the map. To do this, you first need to find out between which parallels of latitude and meridians of longitude is located desired point. For example, the point is between 40° and 45° north latitude, 70° and 75° east longitude(Fig. 32). To more accurately define latitude on the map, using a ruler, we measure the distance (AB) between the two parallels, as well as the distance between the lower parallel and the point H (AN). Segment on the map AB equals 5°.
Rice. 32. Definition of a coordinate point.
To the distance AN Add 40 degrees in degrees. If instead AN we would measure the HV and subtract this distance in degrees from 45 °, then we would still get the same result.
Longitude on the map is determined by the same method. Measure the segments SD and CH with a ruler.
We add 70 ° to the obtained value in degrees and get the longitude of the point H. Just as in determining the line of latitude, instead of the segment CH segment can be measured DN. Then subtract the value obtained from 75°.
Rice. 33. Parts graticules on various maps.
1. According to Figure 33, determine which maps each degree grid belongs to?
2. Find on the map of the hemispheres a point indicated by only one of the coordinates.
3. On the map of Kazakhstan, determine the approximate geographical coordinates of your area.
