3 Longitude and Latitude Imaginary lines that are drawn around Earth to help geographers study location of places.Latitude: Horizontal lines that run EAST to WEST. Latitude is the distance north or south of the Equator, measured in units called degrees.Longitude: Vertical lines that run NORTH to SOUTH. Longitude is the distance east or west of the Prime Meridian, measured in degrees.Philadelphia is located at about 39°N and 75° W on Earth.
4 Equator and Prime Meridian The Equator marks 0 latitude. Think of it as Earth’s belt. It runs directly around Earth’s middle.The Prime Meridian marks 0 longitude. It runs from top to bottom of Earth.Each half of Earth is called a hemisphere.