What is the definition for longitude and latitude?
Latitude lines are lines running parallel to the Equator. Latitude is measured from the equator, with positive values going north and negative values going south. Longitude lines run North and South, the vertical lines on a globe. Longitude is measured from the Prime Meridian (which is the longitude that runs through Greenwich, England), with positive values going east and negative values going west. So, for example, 65 degrees west longitude, 45 degrees north latitude is -65 degrees longitude, +45 degrees latitude.
