Latitude, Longitude, and GPS

Watch

• How We Solved the Greatest Riddle In Navigation ↗Be Smart
• LATITUDE AND LONGITUDE || SOCIAL STUDIES || HOW TO FIND THE COORDINATES ON THE EARTH || GEOGRAPHY ↗Make It Easy Education
• How Do GPS Coordinates Work? ↗BrainStuff - HowStuffWorks
• National Geographic Latitude Longitude ↗Terance Winemiller
• How GPS Works Today ↗BRIGHT SIDE
• The Earth and the Geographic Coordinates ↗Aviation Theory

Read

• Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time ↗An engaging narrative of the centuries-long quest to accurately determine longitude at sea, a problem that vexed empires and claimed countless lives.Dava Sobel
• The Measure of All Things: The Seven-Year Odyssey and Hidden Error That Transformed the World ↗A compelling account of the French expedition to measure the Earth's meridian, revealing the human drama and scientific rigour behind the very definition of the metre and, by extension, our understanding of global coordinates.Ken Alder
• Celestial Navigation: A Complete Course ↗A comprehensive and practical guide to the enduring art of celestial navigation, elucidating the astronomical principles that underpin the determination of latitude and longitude at sea.David Burch
• The Global Positioning System: A Primer ↗An authoritative, accessible introduction to the fundamental principles, applications, and policy implications of the Global Positioning System, essential for understanding modern navigation.National Research Council (US) Committee on the Future of the Global Positioning System
• How GPS WorksA lucid explanation of the fundamental principles behind the Global Positioning System, detailing how satellite signals are used to pinpoint precise locations on Earth.Peter H. Dana
• The Global Positioning System: Theory and ApplicationsA seminal two-part paper by the architects of GPS, offering an unparalleled technical overview of its design, operational principles, and diverse applications.Bradford W. Parkinson and James J. Spilker Jr.

Voices to follow

• Jack Dangermond ↗His vision transformed geographic information systems into a ubiquitous tool for understanding and managing the planet's spatial data.Founder and President, Esri
• Michael F. Goodchild ↗A foundational figure in GIScience, his theoretical insights continue to shape how we conceptualise and analyse geographic information.Emeritus Professor of Geography, University of California, Santa Barbara
• Dava Sobel ↗Her acclaimed work, 'Longitude', masterfully chronicles the historical quest to accurately determine position at sea, a pivotal moment in spatial understanding.Science writer and author
• Mark Monmonier ↗An incisive cartographic critic and historian, he illuminates the power, pitfalls, and political dimensions inherent in mapping and spatial representation.Distinguished Professor of Geography, Syracuse University

Glossary

• CoordinatesCoordinates are a set of numbers or letters that pinpoint an exact location on a map or the Earth's surface. For geography, these are usually latitude and longitude. For example, if someone asks for the coordinates of your school, they want its specific latitude and longitude numbers.
• EquatorThe Equator is an imaginary line that circles the Earth exactly halfway between the North Pole and the South Pole. It divides the Earth into the Northern Hemisphere and the Southern Hemisphere. For example, countries like Kenya and Ecuador are located right on or very close to the Equator.
• GPS (Global Positioning System)GPS is a satellite-based system that helps you find your exact location anywhere on Earth. It uses signals from satellites orbiting the Earth to figure out your latitude and longitude. For example, when you use Google Maps on your phone to find directions, you're using GPS.
• Grid SystemA grid system is a network of intersecting lines, like a checkerboard, used on maps to help locate places. On Earth, the lines of latitude and longitude form a global grid system. For example, when you look at a world map with crisscrossing lines, you're seeing the latitude and longitude grid that helps you find any spot.
• HemisphereA hemisphere is one half of the Earth. The Equator divides the Earth into the Northern and Southern Hemispheres, while the Prime Meridian divides it into the Eastern and Western Hemispheres. For example, India is located entirely in the Northern and Eastern Hemispheres.
• LatitudeLatitude tells you how far north or south a place is from the Equator, an imaginary line around the middle of the Earth. It's measured in degrees, from 0° at the Equator to 90° at the North and South Poles. For example, if your city has a latitude of 28° North, it means it's 28 degrees north of the Equator.
• LongitudeLongitude tells you how far east or west a place is from the Prime Meridian, another imaginary line that runs from the North Pole to the South Pole through Greenwich, England. It's also measured in degrees, from 0° at the Prime Meridian to 180° east or west. For example, if your city has a longitude of 77° East, it means it's 77 degrees east of the Prime Meridian.
• North PoleThe North Pole is the northernmost point on Earth, located at 90 degrees North latitude. It's where all lines of longitude meet. For example, Santa Claus is often said to live at the North Pole.
• Prime MeridianThe Prime Meridian is an imaginary line that runs from the North Pole to the South Pole, passing through Greenwich, England. It's the starting point (0 degrees) for measuring longitude, dividing the Earth into the Eastern Hemisphere and Western Hemisphere. For example, if you're standing on the Prime Meridian, places to your east have east longitudes, and places to your west have west longitudes.
• South PoleThe South Pole is the southernmost point on Earth, located at 90 degrees South latitude. Like the North Pole, all lines of longitude meet here. For example, Antarctica is the continent that surrounds the South Pole.

Threads 5

Where this connects to other fields, and why it's worth knowing.

• Digital Authoritarianism Political Science

  You can't be taxed, drafted, or arrested by a government that can't find you. So when a state gives every shack an address, it isn't just helping the mail arrive, it's making people visible to power. Putting the poor on the map is service and surveillance at the same time.

• Neuroscience Psychology

  Deep in your brain sit special cells that draw a live map of wherever you are, your own built-in GPS. But like any muscle, if you never use it, it weakens. Lean on your phone's GPS for every turn and that inner mapmaker may quietly start to fade.

• Cryptography & Digital Security Mathematics

  Your phone finds itself by listening to signals from GPS satellites, but those signals carry no signature and no proof they're real. Your phone just trusts them. That means anyone with a cheap gadget can broadcast fake signals and make your phone think it's somewhere else, which is a scary hole in everything from ships to war drones.

• Black Holes Science

  GPS satellites carry clocks that tick at a slightly different speed than clocks on the ground, because gravity and their high speed bend time (that's Einstein's relativity). If engineers ignored that tiny difference, your map location would drift off by about ten kilometers every single day.

• Pandemics Science

  In 1854 London, a doctor named John Snow stopped a cholera outbreak by drawing deaths on a map and spotting they circled one water pump. That simple map invented disease detective work by location, the exact same idea your phone now does automatically for contact tracing.