The horizontal lines on a map are called latitude lines. The vertical lines show longitude and are also known as meridians. Latitude and longitude are broken into degrees, minutes, seconds and directions, starting with latitude. For instance, an area with coordinates marked 41° 56’ 54.3732” N, 87° 39’ 19.2024” W would be read as 41 degrees, 56 minutes, 54.3732 seconds north; 87 degrees, 39 minutes, 19.2024 seconds west.
There are other ways to write geographical coordinates but Stories from the Road uses the form above.
Fun fact: On a Windows computer keyboard, you can insert a Degree symbol by holding down the ALT key and tapping 0176 on the number pad.
Here’s a website that explains geographical coordinates in more detail: