Our distances are not driving distances, but are calculated as a 'straight-line' (or point-to-point) distance from Lock Three. A straight line distance ignores obstructions like rivers, canyons, lakes, et cetera - it's truly a line drawn from Point A (ie- Lock Three) to Point B.
Our distance measurements begin at a specific point in Lock Three. The point that we are using is located at these GPS coordinates - Latitude: 34.8118, Longitude: -87.4106 [Map]. In this case, the coordinates for Lock Three have been provided by the Geographic Names Information System (GNIS).