Latitude and longitude are used to locate positions on the Earths surface. Parallels of latitude are the circles that are parallel to the equator from the poles, and they are measured in degrees, minutes, and seconds of a point north or south of the equator. Lines joining places with the same latitudes are called parallels. The value of the equator is 0°, and the latitude of the poles is 90°N and 90°S. If parallels of latitude are drawn at an interval of one degree, there will be 89 parallels in the northern and southern hemispheres each.

Meridians of longitude are the lines of reference running from the North Pole to the South Pole, and they are also measured in degrees, minutes, and seconds. The meridian which passes through Greenwich is known as the Prime Meridian. Longitude is measured east or west of the Prime Meridian, and it is the amount of arc created by drawing a line from Earths center to the intersection of the Equator and the Prime Meridian and then another line from Earths center to any point elsewhere on the Equator. Longitude is measured 180° both east and west of the Prime Meridian. Lines of longitude are drawn from pole to pole and are at right angles to the Equator. The distance per degree of longitude at the Equator is about 111.32 km (69.18 miles) and at the poles, 0. .

The combination of meridians of longitude and parallels of latitude establishes a framework or grid that can be used to locate exact positions on the Earths surface in reference to the Prime Meridian and the Equator. A point described as 30°15′20″ N subtends an angle of 30°15′20″ at the center of the globe. The combination of latitude and longitude helps us to find the location and time of the place.