The simplest mathematical method to estimate tortuosity is the arc-chord ratio: the ratio of the length of the curve (L) to the distance between the ends of it (C): Arc-chord ratio equals 1 for a straight line and is infinite for a circle.
ERS is a set of computer programs set to run in a specified order on the UNISYS Mainframe at the Enterprise. Computing Center in Martinsburg, West Virginia and the Enterprise Computing Center in Memphis, (ECC-MTB and. ECC-MEM) Tennessee. All ERS information is housed on the ERS database at each computing center.
AIS-Using the Benefits of the Automatic Identification System. What is AIS and who has it? The Universal Shipborne Automatic Identification System (AIS) is a vessel tracking system capable of communicating navigation information automatically between AIS equipped vessels and coastal authorities.