Our distances are not driving distances, but are calculated as a 'straight-line' distance. A straight line distance ignores obstructions like rivers, canyons, lakes, et cetera - it's truly a line from Point A (ie- Green Grass) to Point B.Our distance measurements begin at a specific point in Green Grass. The point we use is located at these GPS coordinates - Latitude: 45.1711, Longitude: -101.2460 In this case, the coordinates for Green Grass have been provided by the Geographic Names Information System (GNIS).