Method for determining ship berthing water area based on AIS data

Abstract

The invention relates to the technical field of ship traffic management, in particular to a ship berthing water area determination method based on AIS data, and the method comprises the following steps: collecting AIS data of a ship, including defining dynamic data, static data, an anchoring ground area omega convex hull and an anchoring event of the ship; based on the AIS data, detecting an anchoring event by using a three-dimensional joint filtering model of space, motion and time; carrying out ship contour modeling on the detected anchoring event to obtain a dynamic contour vertex set of a ship; a Welzl algorithm is used for solving the minimum circumcircle of the dynamic contour vertex set, and then the berthing water area of the ship is determined. According to the invention, accurate identification of the anchored ship and automatic high-precision calculation of the actually occupied area of the anchored water area can be carried out, so that the ship anchored water area is determined, and fine configuration and dynamic safety management of space resources of the port anchored ground are facilitated.

Description

Technical Field

[0001] This invention relates to the field of ship traffic management technology, and in particular to a method for determining ship berthing areas based on AIS data. Background Technology

[0002] Anchorages are crucial supporting infrastructure for ports, playing a vital role in port operations. However, some port anchorages are currently operating at overcapacity, leading to difficulties in anchoring. Accurate identification of anchored vessels and automated, high-precision calculation of their actual occupied berthing area can provide theoretical and methodological support for the refined allocation and dynamic safety management of port anchorage space resources, thereby addressing the aforementioned problems to some extent. However, currently, there is no sufficiently accurate and reliable scheme for determining vessel berthing areas. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method for determining ship mooring areas based on AIS data.

[0004] To achieve the above objectives, this invention provides a method for determining ship berthing areas based on AIS data. The method includes the following steps: collecting ship AIS data, including defining the ship's dynamic data, static data, anchorage area Ω convex hull, and anchoring events; detecting anchoring events using a three-dimensional joint filtering model of space, motion, and time based on the AIS data; modeling the ship's contour for the detected anchoring events to obtain a dynamic contour vertex set; and using the Welzl algorithm to solve for the minimum circumcircle of the dynamic contour vertex set, thereby determining the ship's berthing area. This invention enables accurate identification of anchored ships and automated, high-precision calculation of their actual occupied berthing area, thus determining the ship's berthing area, which is beneficial for the refined allocation and dynamic safety management of port anchorage space resources.

[0005] Optionally, the dynamic data is defined as:

[0006] in, This refers to the dynamic data. For the first The maritime mobility service identification code of a ship. The timestamp for the i-th recording of the dynamic data is the UTC timestamp. Let be the latitude value of the ship when the dynamic data is recorded for the i-th time. The longitude value of the ship at the time of the i-th recording of the dynamic data. Let be the ship's ground speed during the i-th recording of the dynamic data. The navigation state of the ship at the time of the i-th recording of the dynamic data. Let N be the heading of the ship when the dynamic data is recorded for the i-th time, and N be the total number of dynamic data records.

[0007] Optionally, the static data is defined as:

[0008] in, This refers to the static data. For the first The maritime mobility service identification code of a ship. The j-th record of the static data is the UTC timestamp. Let j be the length of the ship corresponding to the j-th record. Let j be the ship's width corresponding to the j-th record. For the j-th record, the corresponding ship type, The distance from the bow to the bridge. This is the distance from the stern to the bridge. This is the distance from the starboard side to the bridge. This is the distance from the port side to the bridge. M represents the ship's draft, and M represents the total number of static data records.

[0009] Optionally, the convex hull of the anchorage region Ω is defined as:

[0010] in, The convex hull of the anchorage region Ω represents the convex hull operation. Let k be the k-th point within the anchorage. for The longitude value, for The latitude value, K is the total number of points within the anchorage. It is a two-dimensional real number space.

[0011] Optionally, the anchoring event is defined as:

[0012] Where E represents the anchoring event, MMSI is the vessel's Maritime Mobility Service Identifier, and Voyage is the voyage information. The anchorage start time. This is the end time of anchorage. is the anchorage duration, and n is the number of trajectory points.

[0013] Optionally, the three-dimensional joint filtering model satisfies the following relationship:

[0014] Wherein, ValidAnchor represents the three-dimensional joint filtering model. This is the latitude value of the ship. This is the longitude value of the ship. The Ω-shaped convex hull of the anchorage region is represented by [insert Ω here]. For the ship's speed relative to the ground, Where S is the speed threshold and S is the ship's navigation state. For the duration of anchoring, To minimize the duration of anchoring activities.

[0015] Optionally, the step of modeling the ship's profile based on the detected anchoring event to obtain a dynamic profile vertex set of the ship includes the following steps: After the mooring event is detected, the ship profile is modeled in the local coordinate system based on the corresponding static data, and the local coordinates of the vertices of the ship profile are obtained. Mapping the local coordinates of the vertices to the global coordinate system yields the geographic coordinates of each of the ship's hull outline vertices; Traverse the set of anchoring durations for the anchoring events, accumulate the geographic coordinates of the ship's hull profile vertices at the corresponding times, and form the dynamic profile vertex set of the ship in the anchoring event.

[0016] Optionally, the local coordinates of the vertex satisfy the following relationship:

[0017] in, , , , and These are the five vertices of the ship's hull profile in the local coordinate system. , , , and In order , , , and The local coordinates of the vertex, This is the distance from the stern to the bridge. This is the distance from the port side to the bridge. For the bow direction, This is the distance from the starboard side to the bridge. L is the distance from the bow to the bridge, and L is the length of the ship.

[0018] Optionally, the mapping formula from the vertex local coordinates to the geographic coordinates is:

[0019] in, and These are the latitude and longitude in the global coordinate system, respectively. Let r be the geographic coordinates of the r-th vertex of the hull outline. and These are the latitude and longitude of the origin in the local coordinate system, respectively. Let be the local coordinates of the r-th vertex of the hull profile. For the bow direction, The radius is the WGS-84 ellipsoid.

[0020] Optionally, the dynamic contour vertex set is defined as:

[0021] in, This refers to the set of vertices of the dynamic contour. The anchorage start time. This is the end time of anchorage. For the r-th vertex of the hull profile in the time interval The geographic coordinates of time t.

[0022] The present invention has at least the following beneficial effects: 1. Based on the collection of AIS data of ships and the definition of dynamic data, static data of ships, anchorage area Ω convex hull and anchoring events, a three-dimensional joint filtering model is used to achieve accurate detection of anchoring events, thereby achieving accurate identification of anchored ships.

[0023] 2. Based on the accurate identification of anchored vessels, and taking into account the geometric contour features of the vessels, a method for quantifying the anchorage area based on the Welzl algorithm is proposed. By solving the minimum enclosing circle of the dynamic contour point set of the vessel, the method realizes the automated and high-precision calculation of the actual area of ​​the anchored vessel occupied by the vessel, thereby determining the vessel's anchorage area. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating a method for determining a ship's mooring area based on AIS data, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a ship outline model according to an embodiment of the present invention; Figure 3 This refers to the actual anchoring radius of the ship, the distribution of trajectory points, and the minimum enclosing circle in an embodiment of the present invention. Detailed Implementation

[0026] Specific embodiments of the present invention will now be described in detail. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other instances, well-known circuits, software, or methods have not been specifically described to avoid obscuring the invention.

[0027] Throughout this specification, references to "an embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "in an embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale.

[0028] It should be noted in advance that, in one alternative embodiment, except for independent descriptions, the same symbols or letters appearing in all formulas have the same meaning and value.

[0029] In one optional embodiment, please refer to Figure 1 This invention provides a method for determining the mooring area of ​​a ship based on AIS data, the method comprising the following steps: S1. Collect AIS data of the vessel, including defining the vessel's dynamic data, static data, anchorage area Ω hull, and anchoring events.

[0030] Specifically, in this embodiment, the ship's AIS data includes the ship's status information. For example, an AIS status code of "1" indicates that the ship is in an "anchored state." Therefore, it is generally possible to determine whether a ship is anchored by using the AIS status code. However, when anchoring, the ship's helmsman often changes the ship's AIS status from "at sea" to "anchored" only after a certain period of time has elapsed since anchoring; and then changes the status back to "at sea" only after a certain period of time has elapsed since anchoring.

[0031] Therefore, it is inaccurate to determine a vessel's anchorage status solely based on AIS status codes and thus the actual area occupied by the vessel's anchorage. Considering this, this embodiment will subsequently employ a three-dimensional joint filtering model of space, motion, and time, driven by data, to achieve high-precision anchoring event detection, providing a foundation for the spatial identification and quantification of vessel anchorage. Prior to this, it is necessary to collect the vessel's AIS data and define the vessel's dynamic data, static data, anchorage area Ω convex hull, and anchoring events for subsequent explanation.

[0032] In this embodiment, the ship's dynamic data, static data, anchorage area Ω convex hull, and anchoring events are defined as follows:

[0033]

[0034]

[0035]

[0036] in, Represents dynamic data. For the first The maritime mobility service identification code of a ship. This is the UTC timestamp for the i-th record of dynamic data. Let be the latitude value of the ship when the dynamic data is recorded for the i-th time. Let be the longitude value of the ship at the time of the i-th recording of dynamic data. Let be the ship's ground speed during the i-th recording of dynamic data. Let i represent the ship's navigation state at the time of the i-th dynamic data recording. Let N be the ship's heading at the i-th time dynamic data is recorded, and N be the total number of dynamic data records. Represents static data. Let j be the UTC timestamp of the j-th record of static data. Let j be the length of the ship corresponding to the j-th record. Let j be the ship's width corresponding to the j-th record. For the j-th record, the corresponding ship type, The distance from the bow to the bridge. This is the distance from the stern to the bridge. This is the distance from the starboard side to the bridge. This is the distance from the port side to the bridge. M represents the ship's draft, and M represents the total number of static data records. The convex hull of the anchorage region Ω is represented by ConvHull, which performs convex hull operations. Let k be the k-th point within the anchorage. for The longitude value, for The latitude value, K is the total number of points within the anchorage. This is a two-dimensional real number space, where E represents the anchoring event, MMSI is the vessel's maritime movement service identifier, and Voyage is the voyage information. The anchorage start time. This is the end time of anchorage. is the anchorage duration, and n is the number of trajectory points.

[0037] S2. Based on the AIS data, use a three-dimensional joint filtering model of space, motion and time to detect anchoring events.

[0038] Specifically, in this embodiment, before detecting anchoring events, the target vessel type can be determined first. Since the main users of the anchorage are cargo ships and tankers, the target vessel types selected in this embodiment are cargo ships and tankers. In AIS data, the codes corresponding to cargo ships are 70-79, and the codes corresponding to tankers are 80-89, thus forming the set of target vessels to be detected. It can be represented as:

[0039] ShipType refers to the type of vessel.

[0040] In dynamic data, the navigation status identifier S represents the ship's navigation status and is the fundamental basis for determining its anchoring status. According to the International Maritime Organization's AIS technical standards, its definition is as follows:

[0041] Anchorages have defined boundaries, and ships typically anchor within them. Therefore, a region-based filtering algorithm can be used to eliminate a large number of non-anchored ships, thus limiting the computation to the anchorage and significantly improving efficiency. Therefore, for any anchored ship, its anchoring trajectory must satisfy the following spatial constraints:

[0042] in, Let b be the b-th trajectory point on the anchoring trajectory. Let b be the latitude value of the b-th trajectory point on the anchoring trajectory. Let be the longitude value of the b-th trajectory point on the anchoring trajectory, and Cluster be the set of trajectory points. Indicates judgment Is it in Inside.

[0043] Meanwhile, ships typically operate at low speeds when anchored, generally less than 2 knots. Therefore, for any anchored ship, its anchoring trajectory must satisfy the following motion constraints:

[0044] in, Let be the speed of the vessel relative to the ground at the b-th point on the anchoring track. This is the speed threshold.

[0045] If the anchoring duration of an anchored vessel is not less than the shortest duration of anchoring activity, and the time interval between two consecutive trajectory points does not exceed a time interval threshold, then the vessel must meet the following time constraints:

[0046] in, The time interval between two consecutive trajectory points. and These represent the times corresponding to the two trajectory points before and after; The time interval threshold is set to 600 seconds. , These are the start and end times of anchorage, respectively. The duration of anchorage in a steady state; To minimize the duration of anchoring activities. It needs to be determined based on the actual conditions of the port. For example, if a port is a semi-diurnal tidal port, it typically has two high tides and two low tides per day. The effective anchorage time for ships generally covers at least half of the tidal cycle. The minimum value is 6 hours.

[0047] With the navigation state identifier S set to 1, based on the spatial, kinematic, and temporal constraints given above, the three-dimensional joint filtering model of space, motion, and time can be expressed as follows:

[0048] Wherein, ValidAnchor represents the three-dimensional joint filtering model. This is the latitude value of the ship. This is the longitude value of the ship. This represents the ship's speed relative to the ground. Among them, This indicates that the ship must meet spatial constraints. This indicates that the ship must meet motion constraints. This indicates that the ship's navigation status must be at anchor. This indicates that the ship must meet time constraints. This model can be used to filter out anchoring events that meet the requirements in all three dimensions: space, motion, and time.

[0049] Furthermore, after obtaining the set of anchoring events, abnormal ship trajectories can be eliminated by ship voyage, i.e.:

[0050]

[0051]

[0052] in, The voyage identifier is voyage c, and the exclusion criteria represent the exclusion rules. For the (b+1)th trajectory point on the anchoring trajectory, for and The distance between them This represents the average distance traveled during the voyage. This represents the standard deviation of the distance within the voyage.

[0053] S3. Model the ship's profile based on the detected anchoring events to obtain the dynamic profile vertex set of the ship.

[0054] When anchored, ships typically move in an approximately circular motion around their anchor point. However, due to random disturbances caused by environmental factors such as wind, waves, and currents, the actual set of ship positions often exhibits a near-circular distribution. The spatial extent of this distribution is strictly constrained by its minimum enclosing circle. Therefore, this embodiment comprehensively considers the ship's geometric profile characteristics and proposes a method for quantifying the ship's anchoring area based on the Welzl algorithm. This method accurately characterizes the actual circular water area occupied by the ship's anchorage by solving for the minimum enclosing circle of the ship's dynamic profile vertex set. Step S3 specifically includes the following steps: S31. After the mooring event is detected, the ship profile is modeled in the local coordinate system based on the corresponding static data, and the local coordinates of the vertices of the ship profile are obtained.

[0055] Specifically, in this embodiment, upon detecting an anchoring event, the corresponding static data for that event can be obtained. Then, a local coordinate system can be constructed with the ship's bridge as the origin, and the ship's profile can be modeled in this local coordinate system based on the static data. This allows for the determination of the local coordinates of the vertices of the ship's profile. Specifically, as follows... Figure 2 As shown. Figure 2 In the equation, the local coordinates of the vertices satisfy the following relationship:

[0056] in, , , , and These are the five vertices of the ship's hull profile in the local coordinate system. , , , and In order , , , and The local coordinates of the vertex, The direction of the bow is L, and the length of the ship is L.

[0057] S32. Map the local coordinates of the vertices to the global coordinate system to obtain the geographic coordinates of each of the hull outline vertices.

[0058] Specifically, in this embodiment, after obtaining the local coordinates of the vertices of the hull outline, the coordinates in the local coordinate system are further mapped to the global coordinate system through the following relationship to obtain the geographic coordinates of each hull outline vertex.

[0059]

[0060] in, and These are latitude and longitude in the global coordinate system, respectively. Let be the geographic coordinates of the r-th vertex of the hull outline. and These represent the latitude and longitude of the origin in the local coordinate system, respectively. Let be the local coordinates of the r-th vertex of the hull profile. The radius is the WGS-84 ellipsoid.

[0061] S33. Traverse the set of anchoring durations of the anchoring event, accumulate the geographic coordinates of the ship's outline vertices at the corresponding times, and form the dynamic outline vertex set of the ship in the anchoring event.

[0062] Specifically, in this embodiment, since an anchoring event corresponds to a series of discrete ship position sets, the set of anchoring durations of the anchoring event can be traversed to accumulate the geographic coordinates of the ship's hull contour vertices at the corresponding times, forming a dynamic contour vertex set of the ship in the anchoring event, i.e.:

[0063] in, For dynamic contour vertex set, The anchorage start time. This is the end time of anchorage. For the r-th hull profile vertex in the time interval The geographic coordinates of time t.

[0064] S4. Use the Welzl algorithm to find the minimum circumcircle of the dynamic contour vertex set, and then determine the mooring area of ​​the ship.

[0065] Specifically, in this embodiment, after obtaining the dynamic contour vertex set of the vessel during the anchoring event through step S3, the Welzl algorithm can be used to solve for the minimum circumcircle of the dynamic contour vertex set. The water area encompassed by this minimum circumcircle is the corresponding vessel's anchoring water area. The minimum circumcircle obtained using the Welzl algorithm must be one of the following three: 1. Single-point circle: When there is only one point in the set of vertices of the dynamic contour, the center of the smallest circumcircle is that point, and the radius is 0.

[0066] 2. Diameter circle: When the vertices of the dynamic contour are concentrated at two points or all points are collinear, the center of the smallest circumcircle is the midpoint of the line segment, and the radius is half of the line segment.

[0067] 3. Three-point circumcircle: When the vertices of a dynamic contour are concentrated at three non-collinear points, the center of the smallest circumcircle is the circumcenter of the triangle formed by these three points, and the radius is... , , and Let s be the lengths of the three sides of the triangle, and s be the area of ​​the triangle.

[0068] To verify the effectiveness of this method, this embodiment takes a typical cargo ship in a port as an example. The ship anchored 11 times in the port in 2020, with a total of 5065 track points. The anchoring records of the first 9 times are shown in Table 1.

[0069] Table 1. Anchorage records of typical cargo ships in a certain port.

[0070] Furthermore, the actual anchoring radius, trajectory point distribution, and minimum enclosing circle obtained using this method for the first nine voyages of this typical cargo ship are shown below. Figure 3 As shown. From Figure 3 It is easy to see that the radius of the minimum enclosing circle obtained by this method is almost the same as the actual anchorage radius of the typical cargo ship, which verifies the effectiveness of this method.

[0071] It should be noted that in some cases, the actions described in the specification can be performed in different orders and still achieve the desired results. In this embodiment, the order of steps is given only to make the embodiment clearer and easier to explain, and not to limit it.

[0072] This invention has at least the following beneficial effects: Based on the collection of AIS data of ships and the definition of dynamic data, static data of ships, Ω-convex hull of anchorage areas, and anchoring events, a three-dimensional joint filtering model is used to achieve accurate detection of anchoring events, thereby achieving accurate identification of anchored ships; based on the accurate identification of anchored ships, and considering the geometric contour features of ships, a method for quantifying anchorage water areas based on the Welzl algorithm is proposed. By solving the minimum enclosing circle of the dynamic contour point set of ships, the actual area of ​​anchored ships occupied by anchored ships is automatically calculated with high precision, thereby determining the anchorage water area of ​​ships, providing theoretical and methodological support for the refined allocation and dynamic safety management of port anchorage space resources.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for determining the berthing area of ​​a ship based on AIS data, characterized in that, Includes the following steps: Collect AIS data of ships, including defining the ship's dynamic data, static data, anchorage area Ω hull, and anchoring events; Based on the AIS data, a three-dimensional joint filtering model of space, motion, and time is used to detect anchoring events; The detected anchoring events are modeled to obtain a dynamic set of ship profile vertices. The Welzl algorithm is used to find the minimum circumcircle of the dynamic contour vertex set, thereby determining the ship's mooring area.

2. The method for determining ship berthing areas based on AIS data according to claim 1, characterized in that, The dynamic data is defined as follows: ， in, This refers to the dynamic data. For the first The maritime mobility service identification code of a ship. The timestamp for the i-th recording of the dynamic data is the UTC timestamp. Let be the latitude value of the ship when the dynamic data is recorded for the i-th time. The longitude value of the ship at the time of the i-th recording of the dynamic data. Let be the ship's ground speed during the i-th recording of the dynamic data. The navigation state of the ship at the time of the i-th recording of the dynamic data. Let N be the heading of the ship when the dynamic data is recorded for the i-th time, and N be the total number of dynamic data records.

3. The method for determining ship berthing areas based on AIS data according to claim 1, characterized in that, The static data is defined as follows: ， in, This refers to the static data. For the first The maritime mobility service identification code of a ship. The j-th record of the static data is the UTC timestamp. Let j be the length of the ship corresponding to the j-th record. Let j be the ship's width corresponding to the j-th record. For the j-th record, the corresponding ship type, The distance from the bow to the bridge. This is the distance from the stern to the bridge. This is the distance from the starboard side to the bridge. This is the distance from the port side to the bridge. M represents the ship's draft, and M represents the total number of static data records.

4. The method for determining ship berthing areas based on AIS data according to claim 1, characterized in that, The convex hull of the anchorage region Ω is defined as: ， in, The convex hull of the anchorage region Ω represents the convex hull operation. Let k be the k-th point within the anchorage. for The longitude value, for The latitude value, K is the total number of points within the anchorage. It is a two-dimensional real number space.

5. The method for determining ship berthing areas based on AIS data according to claim 1, characterized in that, The anchoring event is defined as follows: ， Where E represents the anchoring event, MMSI is the vessel's Maritime Mobility Service Identifier, and Voyage is the voyage information. The anchorage start time. This is the end time of anchorage. is the anchorage duration, and n is the number of trajectory points.

6. The method for determining ship mooring areas based on AIS data according to claim 1, characterized in that, The three-dimensional joint filtering model satisfies the following relationship: ， Wherein, ValidAnchor represents the three-dimensional joint filtering model. This is the latitude value of the ship. This is the longitude value of the ship. The Ω-shaped convex hull of the anchorage region is represented by [insert Ω here]. For the ship's speed relative to the ground, Where S is the speed threshold and S is the ship's navigation state. For the duration of anchoring, To minimize the duration of anchoring activities.

7. The method for determining ship berthing areas based on AIS data according to claim 1, characterized in that, The process of modeling the ship's profile based on the detected anchoring events to obtain a dynamic profile vertex set for the ship includes the following steps: After the mooring event is detected, the ship profile is modeled in the local coordinate system based on the corresponding static data, and the local coordinates of the vertices of the ship profile are obtained. Mapping the local coordinates of the vertices to the global coordinate system yields the geographic coordinates of each of the ship's hull outline vertices; Traverse the set of anchoring durations for the anchoring events, accumulate the geographic coordinates of the ship's hull profile vertices at the corresponding times, and form the dynamic profile vertex set of the ship in the anchoring event.

8. The method for determining ship berthing areas based on AIS data according to claim 7, characterized in that, The local coordinates of the vertex satisfy the following relationship: ， in, , , , and These are the five vertices of the ship's hull profile in the local coordinate system. , , , and In order , , , and The local coordinates of the vertex, This is the distance from the stern to the bridge. This is the distance from the port side to the bridge. For the bow direction, This is the distance from the starboard side to the bridge. L is the distance from the bow to the bridge, and L is the length of the ship.

9. The method for determining ship mooring areas based on AIS data according to claim 7, characterized in that, The mapping formula from the vertex local coordinates to the geographic coordinates is: ， in, and These are the latitude and longitude in the global coordinate system, respectively. Let r be the geographic coordinates of the r-th vertex of the hull outline. and These are the latitude and longitude of the origin in the local coordinate system, respectively. Let be the local coordinates of the r-th vertex of the hull profile. For the bow direction, The radius is the WGS-84 ellipsoid.

10. The method for determining ship mooring areas based on AIS data according to claim 7, characterized in that, The dynamic contour vertex set is defined as follows: ， in, This refers to the set of vertices of the dynamic contour. The anchorage start time. This is the end time of anchorage. For the r-th vertex of the hull profile in the time interval The geographic coordinates of time t.

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