Today on Earth there is not a single site left that would not be studied by a person or at least not visited! The more information appeared about the surface of the planet, the more relevant the question arose about determining the location of an object. Meridians and parallels, which are elements of a degree grid, help to find the geographical address of the desired point and facilitate the process of orientation on the map.
Cartography History
Humanity did not immediately come to such a simple way of determining the coordinates of an object as calculating its longitude and latitude. Familiar to us all 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 emergence of such sciences as geography and astronomy, which led civilization to create a modern map with a convenient degree grid.
- One of the “founders” of the natural sciences is Aristotle, who was the first to prove that our planet has a spherical shape.
- The ancient Earth travelers were very observant, and they noticed that in the sky (by stars), the direction C (north) - South (south) is easily traced. This line became the first “meridian”, an analogue of which can be found today 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 skafis (an 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 a connection between such sciences as geodesy and astronomy, thereby making it possible to conduct many studies and measurements of terrestrial territories using celestial bodies.
Degree grid
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 viewed on separate pages, which allows a systematic study of any territory. With the development of geographical knowledge, the globe also improved. 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, but already gave an idea of ​​the approximate location of the desired points. Modern maps have the required elements that make up the degree grid. Using it, coordinates are determined.
Degree grid elements
- Poles - North (above) and South (below), are the points at which 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 polar circles (South and North) are located further than 23 parallels towards the poles.
- Prime Meridian. It divides the surface of the Earth 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 B (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 on the 66th parallel to the south and north of the equator.
How to determine the meridians and parallels of the desired point?
Any object on our planet has its latitude and longitude! Even if it is very, very 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 an action plan that can be used to calculate coordinates.
Algorithm for determining the geographical address of an object on a map
- Check the geographic name of the property. Annoying errors occur due to banal carelessness, for example: a student made a mistake in the name of the desired point and determined the wrong coordinates.
- Prepare a satin, sharp pencil or pointer and a magnifying glass. These tools will help to more accurately determine the address of the desired object.
- Select the largest map from the atlas with the desired geographic location. The smaller the scale of the map, the more errors occur during calculations.
- Define the relationship 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 indicated on the map, then find the nearest ones that have a digital designation. The degree of the lines is 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 desired ones. It must be remembered that the elements of the degree grid, in addition to the main lines, can be drawn through any point on the surface of the Earth.
Calculating the size of the territory
- If it is necessary to calculate the size of the object in kilometers, it must be remembered 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: East or West), it is enough from the larger latitude of one of the extreme points, subtract the smaller one 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 located in one of the hemispheres: Southern or Northern), then you need to subtract the smaller one from the larger degree of longitude of one of the extreme points, then multiply the resulting sum by 111 km .
- If the Greenwich meridian passes through the territory of an 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 defined object, then to determine its length from N to S, it is necessary to add the longitude degrees of the extreme points of this direction, and multiply the resulting sum by 111 km.
How to determine the relationship of the object to the main elements of the degree grid?
- If the object is below the equator, then its latitude will be only south, if above - north.
- If the desired point is located to the right of the initial meridian, then its longitude will be eastern, if to the left - western.
- If the object is located above the 66th degree of the north or south parallel, then it enters the corresponding polar region.
Mountain coordinates
Since many mountain systems are long in different directions, and 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. The meridians and parallels of the Caucasus Mountains have different degrees, so what are 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 Elbrus peak, which is 42 degrees 30 minutes north latitude and 45 degrees east longitude.
Himalayas
The highest mountain system on our continent is the Himalayas. Meridians and parallels with different degree degrees cross this object as often as the above. How to determine the coordinates of this system? We do the same 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 peak of Jomolungma, and this is 29 degrees 49 minutes north latitude and 83 degrees 23 minutes and 31 seconds east longitude.
Ural mountains
The longest on our mainland are the Ural Mountains. Meridians and parallels having different degree values ​​cross the given 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. A similar method of determining the coordinates of mountains is acceptable for systems that have a large extent in one of the directions or in both.