Great Circle Route

The shortest distance between two points on a globe is not always a straight line—it’s an arc called a great circle. This complicates long-distance navigation. Rather than stay on a constant heading, pilots must regularly adjust their course to stay on the arc. The great circle effect is most dramatic near the Poles. 

Caption:
The shortest distance between two points on a globe is not always a straight line—it’s an arc called a great circle.
Type: Illustration
Image Date: 2012
Credit: National Air and Space Museum, Smithsonian Institution.
Origin: National Air and Space Museum, Smithsonian Institution.
Creator: Bruce Morser
 
The shortest distance between two points on a globe is not always a straight line—it’s an arc called a great circle.