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There are many ways to locate places on Earth. You can use landmarks like rivers, road signs, and buildings to give you directions. You can use a compass to find north. If you’re in an urban center, you might get by with simple street addresses. But when traveling through an unfamiliar area or exploring a new one, these methods of finding locations can be inadequate.For example, let’s say you want to go bird watching somewhere in the world. What if there’s no nearby landmark or sign? Or what if the dense tree cover makes it difficult to see the tops of buildings? In these situations, having an accurate coordinate is essential for navigation. A geographic coordinate system is a way of describing any location on Earth using two numbers called coordinates. Read on to explore some of the most common coordinate systems that are used for navigation and discovery around the globe.

## Latitude and Longitude

Latitude and longitude are the two primary geographic coordinate systems used by the navigation industry. Latitude is the distance north or south of the equator. Longitude is the distance east or west of the prime meridian — an imaginary line that runs through Greenwich, England. These two measurements are used to identify specific locations on the planet.When navigating using latitude and longitude, you’ll often see these measurements written in a particular format. For example, these locations are at 40 degrees north and 83 degrees west. While this format is common, it can be confusing because it doesn’t clearly communicate the relative distance between locations.

## Finding Latitude and Longitude

There are several ways to find latitude and longitude, but the most accurate method is to use GPS. GPS receivers contain an onboard satellite navigation system that can calculate all the necessary measurements. If you don’t have a GPS receiver, there are a few manual methods that you can use to calculate latitude and longitude.One traditional way to find latitude is to look for the closest parallel of latitude lines. Parallel lines are exactly the same distance from the equator. The parallels get closer together as you move towards the north or south poles.Finding longitude can be trickier because there are no parallel lines. Instead, there are meridian lines that run through Greenwich. The zero degrees meridian line runs through Greenwich.

## Degrees, Decimals, and Coordinate Precision

Coordinates are written in two numbers, separated by a comma. The first number is your latitude and the second number is your longitude. These values are written in degrees, but they can be displayed in decimals. There are 360 degrees in the latitude and longitude lines. Latitude values range from 0 degrees at the equator to 90 degrees at either pole. Longitude values range from 0 degrees at the Greenwich meridian to 180 degrees at the opposite pole.Coordinate precision is the number of significant digits used in a coordinate. For example, a latitude of 38.9818 and a longitude of -122.0833 aren’t as accurate as a latitude of 38.9818 and a longitude of -122.083339.There are also many different types of coordinate systems, each with varying levels of precision. The easiest coordinate systems to use are the ones that display a single number. While these are easy to remember and communicate, they aren’t as accurate as other systems.

## Cartesian Coordinate System

The Cartesian coordinate system uses two axes to define a location. The horizontal axis is known as the x-axis, and the vertical axis is known as the y-axis. The x-axis is the longitude, and the y-axis is the latitude. These two axes intersect at the origin point of 0, 0, which is found in the bottom left corner of the graph.The x-axis can be thought of as the east-west direction. The y-axis can be thought of as the north-south direction. The positive direction for both axes is towards the top of the graph. For example, a location in the eastern hemisphere with a longitude of 30 degrees and a latitude of 45 degrees would have an x-value of 30 and a y-value of 45.

Google Maps uses a coordinate system known as the Google Maps Geographical Information System (GIS) Map. The GIS Map uses the Universal Transverse Mercator (UTM) projection to display a map of the world. It can be rotated and zoomed like a standard Google Map.A single location on the GIS Map is identified using a pair of numbers. The first number is the UTM zone, and the second number is the square on the map.For example, a location at 40 degrees north and 80 degrees west would have a zone value of 40 and a square value of 16.

## Geocaching Coordinates

Geocaching is a treasure hunting game played by more than 3 million people around the world. It uses a unique coordinate system to identify hidden geocaches.The Geocache Data Description (GDD) coordinate system uses three numbers to identify a location: the decimal degrees, the degrees of the magnetic variation, and the grid variation.

## Summary

Latitude and longitude are the two main coordinate systems used to identify a location. Latitude is the distance north or south of the equator, and longitude is the distance east or west of the prime meridian. These two values are used to locate specific places on the planet.The most accurate way to find latitude and longitude is to use GPS. There are several manual methods that can be used if you don’t have a GPS receiver. There are also many different types of coordinate systems, each with varying levels of precision. The easiest systems to use are the ones that display a single number.  