Latitude

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Overview

Latitude is used in navigation and on maps to measure north-south distances. When drawn on maps, latitude is shown as straight, parallel lines running from east (right) to west (left). The 0-latitude line is the equator, which is the point exactly half-way between the north pole and south pole.

See also: longitude - used to measure east-west distances.

How is Latitude Measured

Latitude is measured from the equator, which is 0 degrees, to either the north or south. For all points north of the equator, the location is expressed as "north latitude." For all points south of the equator, the location is expressed as "south latitude."

The distance from the equator to either the north or south pole is exactly 90 degrees of latitude, corresponding to a right angle. Each degree of latitude is approximately:

• 60 nautical miles. Nautical miles are the miles commonly used for ocean navigation and are also commonly used by NASA for spacecraft navigation. They were originally defied to be exactly 1/60 of a degree, but increased accuracy in measurements have changed the value slightly.
• 69 statute miles. Statute miles are the miles normally used for land-based navigation, such as driving.
• 111 kilometers.

Each degree of latitude can be broken down into 60 minutes of latitude. Each minute of latitude can be further broken down into 60 seconds of latitude. Seconds can be further broken down by using fractions of seconds. One second of latitude is approximately 300 meters or 1000 feet. Hand-held GPS units of the type typically carried by hikers can typically measure to an accuracy of 5 meters, or approximately .02 seconds of latitude.

How to Express Latitude

Latitude is normally expressed in spoken form as, "44 degrees, 27 minutes, 39.71 seconds North Latitude" or "44 degrees, 27 minutes, 39.71 seconds North. Latitude is always given before longitude. Often, this degree of accuracy is not required, so it's common to round to the nearest whole second.

Latitude is expressed in written form as 44°27'39.71"N. Note that the single quote means minutes and the double quote means seconds while used in latitude and longitude, not feet and inches.

Full coordinates are given as "44 degrees, 27 minutes, 39.71 seconds North, 110 degrees, 49 minutes, 14.95 seconds West. Elevation is rarely stated for location information. If used, it can be added as "Elevation 7379 feet" or "Elevation 2249 meters".