What is the GPS and how does it assist you in finding location and elevation on Earth? Give a couple of examples where GPS technology was utilized to correct heights for some famous mountains.

The Global Positioning System (GPS) is a remarkable technological innovation that has revolutionized navigation and mapping. Fundamentally, it consists of a network of satellites that transmit signals which are picked up by GPS receivers on the Earth's surface. These receivers can be in smartphones, dedicated GPS devices, or even embedded in various types of transportation.

When we talk about GPS, we're referring to a satellite-based navigation system that allows the determination of the precise location of an object on Earth. The system operates by using at least four satellites to get accurate readings. The more satellite signals a GPS receiver can process, the more accurate its computation of position and elevation will be. This accuracy is crucial for a variety of applications, ranging from everyday navigation by individuals to advanced scientific research and military operations.

To comprehend the practical applications of GPS, one must first understand the concepts of latitude and longitude, which form the basis of our global coordinate system. Latitude is the measure of how far north or south an object is from the Equator, while longitude is the measure of how far east or west an object is from the Prime Meridian.

Together, these two sets of lines create a grid that covers Earth's surface, allowing us to assign a unique set of coordinates to every point on the planet. GPS uses this system to provide accurate location data. For example, the coordinates of the Eiffel Tower in Paris, France, are approximately 48.8584° N latitude and 2.2945° E longitude. With this information, anyone with a GPS device can find the tower, or any other landmark, with considerable ease.

GPS technology isn't limited to pinpointing a location on a two-dimensional plane; it also provides elevation data, which is the height above or below a reference point, usually mean sea level. This is achieved by triangulation, which is the method of calculating a position by measuring the distances to it from known points at either end of a fixed baseline, rather than measuring distances directly.

The altitude given by GPS systems is not merely useful for hikers and pilots, but also plays an essential role in fields like geology, surveying, and construction where knowing the lay of the land is paramount. Accurate elevation data can help in predicting natural disasters like floods, aiding rescue operations, and even in the development of infrastructure, such as in the planning stages of buildings and roads.

Height measurements for mountains have historically been a complex and challenging task, especially considering the vastness and inaccessibility of some peaks. Advances in GPS technology have allowed for much more accurate surveys of mountain heights. High-precision GPS devices can be transported to the summits of mountains by teams of mountaineers, researchers, or even by autonomous drones.

Revised Heights of Famous Mountains

• In 2020, an update to Mount Everest's height was announced, which was the result of a GPS-based survey jointly conducted by China and Nepal, confirming the new official height at 8,848.86 meters (29,031.7 feet).
• The revision of North America's tallest peak, Denali, saw its official height slightly reduced from 20,320 feet to 20,310 feet after GPS survey data was analyzed in 2015.

These corrections not only reflect the natural changes that mountains may undergo, such as earthquake-induced shifts or glacial melting but also showcase the importance of GPS in accurate geographic measurements.