Why do we need geographic coordinates?

To travel, you need at least some knowledge of where to go. Better yet, firmly understand where you are going to hit, and how best to go from point A to point B. There are maps for this. In contrast to plans (cities or a relatively small area Terrain), they have a larger scale and determine the geographical coordinates of objects. This is done for convenience: with the help of these sophisticated figures we can determine whether the given point is to the north or south of the other, and also to the west or east to move us, for example, to get from St. Petersburg to Moscow.

They say: "Language and bring to Kiev," however, even better the way there will prompt geographic coordinates. What it is? These are conditional lines that are plotted on a map or globe. Naturally, in real terrain you will not find them - except that such a sign can be found in some cities that are located directly on a parallel or meridian. Let's consider what latitude and longitude are. Our planet has the shape of an ellipse, that is, not an ideal ball, but slightly compressed to the poles. But for ease of reference, the coordinates are plotted as if the Earth is an absolute sphere.

It, as you know, revolves around its axis. Where this axis is in contact with the surface, there are poles - North and South. If we graphically connect them together, we get 360 conditional lines (after all, the sphere has an angle of 360 degrees). These bands on the map or globe are geographic coordinates indicating longitude. There are two important meridians on Earth. First Th - Zero. He passes through the observatory in the town of Greenwich, near London, and therefore is called by his name. The second one is 180 °, approximately coinciding with the Line for the change of dates.

Geographical coordinates have one more parameter - latitude. If we draw a conditional line not along the rotation of our planet, but across, exactly in the middle, then this will be the equator. If the Greenwich meridian divides the sphere into the Western and Eastern Hemispheres, then the zero latitude is to the North and South. Since a right angle lies between the equator and the pole through the center of the Earth, there are 90 parallels in each hemisphere. The North Pole is 90 ° N, and the South Pole is 90 ° S, respectively. All geographical degrees are divided into minutes and seconds.

Thus, any point on the Earth's surface has its latitude and longitude. To determine the geographical coordinates was very important to the mariners, who, being in the middle of the ocean, were devoid of any orientation. They had to understand where and where they were To be fought. They determined the latitude by means of an astrolabe - a special device that indicated the angle of the Sun standing above the horizon at noon.

But in order to calculate the geographical coordinates of cities, towns and other points, a modern person does not need to use such complex instruments at all. It is enough to look at the atlas to determine the longitude and breadth of the geographical object. Parallels are indicated on the right and left, and meridians are at the top and bottom of the cartographic image of the terrain. And with the help of Google you can find out the coordinates of the smallest points not marked on the map with an accuracy of a second.