Today there is not a single site left on Earth that a person has not studied or at least not visited! The more information appeared about the surface of the planet, the more urgent the question arose of determining the location of an object. Meridians and parallels, which are elements of the degree grid, help to find the geographic address of the desired point and facilitate the process of orienting on the map.
History of Cartography
Humanity did not immediately come to such a simple method of determining the coordinates of an object as calculating its longitude and latitude. Familiar to all of us from school, the main lines gradually appeared in the sources of cartographic knowledge. Below is information about several key stages in the history of the formation of such sciences as geography and astronomy, which led civilization to create a modern map withconvenient graticule.
One of the "ancestors" of the natural sciences is Aristotle, who was the first to prove that our planet has a spherical shape
- Ancient travelers of the Earth were very observant, and they noticed that in the sky (by the stars), the direction C (north) - South (south) is easily traced. This line became the first "meridian", the analogue of which today can be found on the simplest map.
- Eratosthenes, who is better known as the "father of the science of geography", made a lot of small and big discoveries that influenced the formation of geodesy. He was the first to use a skafis (ancient sundial) to calculate the height of the sun over the territory of different cities and noticed a significant difference in his measurements, which depended on the time of day and season. Eratosthenes revealed the connection between such sciences as geodesy and astronomy, thereby making it possible to carry out many studies and measurements of terrestrial territories using celestial bodies.
Graticule
Numerous meridians and parallels, intersecting on a map or globe, are connected into a geographic grid consisting of "squares". Each of its cells is limited by lines that have their own degree. Thus, using this grid, you can quickly find the desired object. The structure of many atlases is built in such a way that different squares are considered on separate pages, which makes it possible to systematically study any territory. With developmentgeographical knowledge improved and the globe. Meridians and parallels are available on the very first models, which, although they did not contain all the reliable information about the objects of the Earth, already gave an idea of the approximate location of the desired points. Modern maps have mandatory elements that make up the degree grid. It is used to determine the coordinates.
Graticule elements
- Poles - North (above) and South (below) are the points where the meridians converge. They are the exit points of the virtual line, which is called the axis.
- Arctic circles. The boundaries of the polar regions begin with them. The Arctic Circles (South and North) are located further 23 parallels towards the poles.
- Zero meridian. It divides the Earth's surface into the Eastern and Western hemispheres and has two more names: Greenwich and Initial. All meridians have the same length and connect the poles on the surface of a globe or map.
- Equator. It is the longest parallel, oriented from W (west) to E (east), which divides the planet into the Southern and Northern hemispheres. All other lines parallel to the equator have different sizes - their length decreases towards the poles.
- Tropics. There are also two of them - Capricorn (South) and Cancer (North). The tropics are located at the 66th parallel south and north of the equator.
How to determine the meridians and parallels of the desired point?
Every object on our planet has its own latitude and longitude! Even if he is veryvery small or, conversely, quite large! Determining the meridians and parallels of an object and finding the coordinates of a point is one and the same action, since it is the degree of the main lines that determines the geographical address of the desired territory. Below is a plan of action that you can use when calculating the coordinates.
Algorithm for determining the geographical address of an object on the map
- Check the correct geographical name of the object. Annoying errors happen due to banal inattention, for example: a student made a mistake in the name of the desired point and determined the wrong coordinates.
- Get a satin, sharp pencil or pointer and magnifying glass ready. These tools will help you more accurately determine the address of the object you are looking for.
- Choose the largest map from the atlas that contains the desired geographic point. The smaller the scale of the map, the more errors occur in the calculations.
- Determine the relation of the object to the main elements of the grid. The algorithm of this procedure is presented after the paragraph: "Calculation of the size of the territory".
- If the desired point is not located directly on the line marked on the map, then find the nearest ones that have a digital designation. Degree lines are usually indicated along the perimeter of the map, less often - on the equator line.
- When determining the coordinates, it is important to find out how many degrees the parallels and meridians are located on the map and correctly calculate the required ones. It must be remembered that the elements of the graticule, except for the main lines, can be drawn through any point on the surfaceEarth.
Calculate the size of the territory
- If you need to calculate the size of an object in kilometers, then you need to remember that the length of one degree of grid lines is - 111 km.
- To determine the length of an object from W to E (if it is completely located in one of the hemispheres: Eastern or Western), it is enough to subtract the smaller value from the greater value of the latitude of one of the extreme points and multiply the resulting number by 111 km.
- If you need to calculate the length of the territory from N to S (only if it is all located in one of the hemispheres: Southern or Northern), then you need to subtract the smaller one from the greater degree of longitude of one of the extreme points, then multiply amount received for 111 km.
- If the Greenwich meridian passes through the territory of the object, then to calculate its length from W to E, the degrees of latitude of the extreme points of this direction are added, then their sum is multiplied by 111 km.
- If the equator is located on the territory of the object being defined, then to determine its length from N to S, it is necessary to add the degrees of longitude of the extreme points of this direction, and multiply the resulting amount by 111 km.
How to determine the relation of an object to the main elements of the graticule?
- If the object is below the equator, then its latitude will be only south, if it is above, it will be north.
- If the desired point is located to the right of the initial meridian, then its longitude will be east, if to the left - west.
- If an object is located above the 66th degree north or south parallel, then it is included incorresponding polar region.
Determining the coordinates of mountains
Since many mountain systems have a large extent in different directions, and the meridians and parallels crossing such objects have different degrees, the process of determining their geographical address is accompanied by many questions. Below are options for calculating the coordinates of the high territories of Eurasia.
Caucasus
The most picturesque mountains are located between two water areas of the mainland: from the Black Sea to the Caspian Sea. The meridians and parallels of the Caucasus Mountains have different degrees, so which ones should be considered decisive for the address of this system? In this case, we focus on the highest point. That is, the coordinates of the Caucasus mountain system is the geographical address of the Elbrus peak, which is equal to 42 degrees 30 minutes north latitude and 45 degrees east longitude.
Himalayas
The highest system of mountains on our mainland is the Himalayas. Meridians and parallels, having different degrees, cross this object as often as the above one. How to correctly determine the coordinates of this system? We act in the same way as in the case of the Ural Mountains, we focus on the highest point of the system. Thus, the coordinates of the Himalayas coincide with the address of the Chomolungma peak, and this is 29 degrees 49 minutes north latitude and 83 degrees 23 minutes and 31 seconds east longitude.
Ural Mountains
The Ural Mountains are the longest on our mainland. Meridians and parallels having different degree values intersect this object in different directions. To determine the coordinates of the Ural Mountains, you need to find their center on the map. This point will be the geographical address of this object - 60 degrees north latitude and the same east longitude. This method of determining the coordinates of mountains is acceptable for systems that have a large extent in one of the directions or in both directions.
