There are 180 lines of latitude assigned to the surface of the Earth, not including the equator. Latitude is measured as degrees above or below the equator, which sits at zero degrees and acts as the basis for measurement.
The equator lies halfway between the North Pole and the South Pole. Lines of latitude are always parallel to the equator and equidistant from one another. Every line of latitude is 69 miles away from both the previous line and the next line. The degree designated to each line is the angular distance between it and the equator. Latitudes north of the equator are often termed as "positive," while latitudes to the south are called "negative."