Recently, along with the progress of information communication technology, it is possible to obtain big data such as communication record of SNS and GPS information of car navigation. By analyzing the movement of people and the actual state of road traffic using these data, there is a movement to discover new knowledge and use it for the future. Analysis such as extracting the principal motion line of the moving object is one such attempt. On the other hand, Ships are to be equipped with AIS by 2007, so it is possible to obtain large scale data on vessel traffic. For these background, therefore, by extracting the standard behavior of each ship even on the sea, it can be used for various analyzes in maritime traffic by extracting it as the standard ship track of the ship. Conventionally, attempts to extract standard ship tracks have been made, and this is done by a method of visually confirming the distribution obtained by drawing tracks on a plane. However, the standard ship track by frequency value can not be used for quantitative analysis because the value that appears most frequently is not limited to one. Therefore, in this paper, as standard ship track for each ship by AIS data, we extract the standard ship track by arithmetic mean and compare it with the method by standard ship track by the conventional frequency value. A ship track can be regarded as a curve on a plane. Planar curves can express time and arc length as parameters. Therefore, we calculate the standard ship track by arithmetic mean of each parameter and confirm the difference of the result from the standard ship track by frequency value.
