How to use the map?
Click on any dark blue dot to select a departure port. The dark blue dot becomes a light blue dot to indicate the currently selected departure port.
The destination ports for which the distance from the selected departure port is available are displayed as red dots. Keeping the mouse pointer a few seconds over a red dot will display the distance in a yellow box. Sometimes, it is necessary to slightly move the mouse over the red dot to display (or display again) the yellow box.