Ship track data display method, ship track data display device, and computer-readable recording medium

1. A non-transitory computer-readable recording medium storing a ship track data display program that causes a computer to execute a process comprising:

first extracting particular ship track data for a set of particular ships with a relative distance therebetween being within a predetermined range, from ship track data for a plurality of ships;

second extracting a place where a distance between ship tracks thereof is at a local minimum, from the particular ship track data; and

associatively displaying, for the place, point data of a ship that previously arrives at the place, in the set of particular ships, and point data of another ship at a point of time when the ship that previously arrives at the place arrives at the place, wherein

the displaying includes providing information that is able to readily be determined as to whether a risky case where the particular ships make avoidance behavior thereof is provided, by causing a display to display an image with the point data of the ship and the point data of the another ship being associatively connected with a line segment, at a local minimum point.

2. The non-transitory computer-readable recording medium according to claim 1 , wherein the displaying includes drawing a line segment that connects the point data of a ship that previously arrives at the place and the point data of the another ship at a point of time when the ship that previously arrives at the place arrives at the place.

3. The non-transitory computer-readable recording medium according to claim 2 , wherein the displaying includes displaying the line segment to be distinguishable from another line that connects point data of ships at an identical point of time.

4. The non-transitory computer-readable recording medium according to claim 1 , wherein the first extracting includes extracting, as the particular ship track data, point data at a first predetermined period of time before time of point data with the relative distance being within the predetermined range to point data at a second predetermined period of time after time of the point data with the relative distance being within the predetermined range.

5. The non-transitory computer-readable recording medium according to claim 1 , wherein the second extracting includes extracting a place where the distance between ship tracks is less than or equal to a predetermined distance and the distance between ship tracks is at a local minimum.

6. The non-transitory computer-readable recording medium according to claim 1 , wherein the second extracting includes extracting a place where an amount of a change of the distance between ship tracks from a third predetermined period of time before a point of time when the distance between ship tracks is at a local minimum to the point of time when the distance between ship tracks is at a local minimum is greater than a predetermined amount of a change, or an amount of a change of the distance between ship tracks from a point of time when the distance between ship tracks is at a local minimum to a fourth predetermined period of time thereafter is greater than the predetermined amount of a change, and the distance between ship tracks is at a local minimum.

7. A ship track data display method comprising:

first extracting particular ship track data for a set of particular ships with a distance between ship tracks thereof being less than a predetermined distance, from ship track data for a plurality of ships, by a processor;

second extracting a place where the distance between ship tracks is at a local minimum, from the particular ship track data, by the processor; and

associatively displaying, for the place, point data of a ship that previously arrives at the place, in the set of particular ships, and point data of another ship at a point of time when the ship that previously arrives at the place arrives at the place, wherein

the displaying includes providing information that is able to readily be determined as to whether a risky case where the particular ships make avoidance behavior thereof is provided, by causing a display to display an image with the point data of the ship and the point data of the another ship being associatively connected with a line segment, at a local minimum point.

8. A ship track data display device comprising:

a processor configured to:

extract particular ship track data for a set of particular ships with a distance between ship tracks thereof being less than a predetermined distance, from ship track data for a plurality of ships;

extract a place where the distance between ship tracks is at a local minimum, from the particular ship track data; and

associatively display, for the place, point data of a ship that previously arrives at the place, in the set of particular ships, and point data of another ship at a point of time when the ship that previously arrives at the place arrives thereat, wherein

the displaying includes providing information that is able to readily be determined as to whether a risky case where the particular ships make avoidance behavior thereof is provided, by causing a display to display an image with the point data of the ship and the point data of the another ship being associatively connected with a line segment, at a local minimum point.