What is Latitude and Longitude?

Suppose you are in a ship crossing the ocean, or making your way across some huge dessert that has no landmarks. How could you describe your exact location so that anyonein the world could find you? That is what latitude and longitude do. They provide the means for locating a place anywhere on the earth’s surface.

If we want to locate place a place in terms of its position north or south, we refer to the latitude. We call the line running around the centre of the earth the equator. It has zero latitude. As we go north of the equator, we have north latitude, and as we go south of it, we have south latitude.

Imagines lines drawn around the earth at certain regular distances north and south of the equator. These lines are called "parallels", because they are all parallel to each other and to the Equator. The distance between each line is measured not in miles, but in degress. A degree is 1/360 of a circle.

Every is 15 degress we have another line of latitude. As we reach the north pole we have 90 degres latitude north, and the South Pole we have 90 degress south. Now suppose we want to measure distance east and west. The lines we use are called longitude. But what should our starting point be? A long time ago it was decided to use a line that passed through Greenwich, England, as the zero line for longitude.

Lines of longitude are called "meridians", so the line passing through Greenwich is the prime meridian. As we move east of this line, at distance of 15 degress, we have east longitude, and as we move west, we have west longitude. To get even more exact measurement, a degree is divided into 60 minutes, and a minute into 60 seconds.

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