Lines of latitude measure distance in degrees (°) north (N) and south (S) of the equator, an imaginary line circling the globe halfway between the North and South poles. As you travel north or south of the equator, latitude increases — up to 90° N and 90° S at the poles.
Lines of longitude measure distance in degrees east (E) and west (W) of the prime meridian, an imaginary line that passes through Greenwich, England. The prime meridian is at 0° longitude. As you travel east (E) or west (W) of the prime meridian, longitude increases — up to the 180° meridian in the Pacific Ocean.