Definition: Claudius Ptolemy, a very influential Greek philosopher from Alexandria who lived from about 90-168 A.D., wrote a Geography and used lines of latitude and longitude to locate places on his maps. The lines of latitude run horizontally parallel to each other. The word latitude comes from a Latin word for "wide" (latus>>latitudo). Latitude was measured in stade distances from the equator. Ptolemy's measurements were inaccurate.


Such lines are thought to have been first applied to earth measurement in the second century B.C. by Hipparchus of Nicea (in Bithynia), an astronomer, whose work advanced Babylonian calculations. Hipparchus found a ratio between day lengths to determine latitude.