Idea of Longitude Icon
The image is of a globe with lines on it. There are five lines on the inside of the globe but they are not straight lines. The only straight line is the one down the center. The other lines curve with the outside of the circle. All of the lines are vertical.
This page contains the Longitude vector icon, as well as variations of this icon in different visual styles, and related icons. All icons are in the flat vector style, however, differ by the line thickness, fill, and corner radius.