What is the difference between longitude and latitude?

Longitude and latitude are geographic coordinates that help us pinpoint locations on Earth's surface with accuracy. 

Imagine our planet as a giant grid, with lines running horizontally (latitude) and vertically (longitude) across the entire sphere to create a global address system. Together, latitude and longitude provide precise coordinates for any location on Earth's surface, making navigation, cartography and GPS systems possible. But what sets the two coordinates apart?

Latitude: east to west

Latitude lines, also known as parallels, run horizontally from east to west. There are 180 lines in total that stretch across the Earth's surface. Think of them as the Earth's belts. 

The best-known latitude line is the one in the very middle — the equator — that separates the world into the northern and southern hemispheres. Found exactly halfway between the north and south poles, the equator is defined as 0 degrees or the starting point for measuring latitude.

As you move away from the equator, either north or south, your latitude increases. For instance, traveling to a location with a latitude of 30 degrees north takes you further away from the equator into the northern hemisphere. 

Conversely, if you go to a place with a latitude of 30 degrees south, you are moving further away from the equator towards the southern hemisphere. Latitude is not just useful for locating a place, but it also provides valuable information on climate and temperature changes. Generally, regions closer to the equator experience warmer weather conditions.

Longitude: north to south

Longitude lines are vertical, stretching from the North Pole to the South Pole. There are 360 lines in total, with Greenwich, England designated as the Prime Meridian. This location was chosen because the United States already used it for its national time zone system and it was widely utilized in sea charts, which were vital for global commerce in the late 19th century. This made Greenwich the most beneficial choice for most people and established it as the center of world time. 

Imagine standing at the Prime Meridian and deciding to move east or west. As you travel eastward, your longitude value increases, while moving westward causes it to decrease. For instance, if you want to go to Berlin, it's approximately 13.4050° E of the Prime Meridian, while going to New York will take you approximately 74.0060° W of the Prime Meridian.

The importance of longitude

Longitude is very important for sailors and navigators. A ship trying to reach the Caribbean nation of Jamaica will need its navigators to rely on longitude to determine the correct east-west course, ensuring accurate navigation toward their destination. 

And since the Earth completes a full rotation of 360 degrees in approximately 24 hours, longitude also plays a key role in determining time zones, which is why crossing a longitude line can affect the local time. For instance, if you travel from New York City (Eastern Standard Time, -5 hours UTC) to London (0 hours UTC), you'll need to adjust your clock forward by 5 hours.

What about GPS?

While longitude, latitude and GPS (Global Positioning System) all pinpoint locations on Earth's surface, they are used for different applications and functionalities. 

GPS relies on a network of satellites orbiting the Earth to accurately calculate your position and help you navigate with precision using real-time data. 

Longitude and latitude are static geographic coordinates that provide fixed and defined positions on Earth's grid. Compared to longitude and latitude, GPS delivers more precision and accurate positioning information, while longitude and latitude serve as the foundation for understanding Earth's surface, establishing a reference point for navigation and exploration.

Longitude and latitude are indispensable tools for pinpointing locations on Earth's surface. They form a global address system, enabling accurate navigation, cartography, and the functioning of GPS systems. Understanding these concepts empowers us to explore, navigate and comprehend the vast expanse of our planet.