CN117828508A - Extraction method for loading and unloading events of oil tanker - Google Patents

Abstract

The invention discloses a method for extracting loading and unloading events of a tanker, which comprises the following steps: step one: extracting the moving track of a certain oil tanker within a certain period of time; step two: extracting a berthing track section using a sliding window; step three: carrying out mutation treatment on the tail end of the berthing track section; step four: splitting an event with a plurality of draft change points; step five: repeating the second to fourth steps, and storing all parking track sections into a dictionary; step six: calculating the draft loading and unloading amount per meter according to the maximum and minimum draft values; step seven: traversing all berthing track sections, and screening events according to the size of draft change; step eight: calculating all event related attribute values and storing the event related attribute values into an event table; step nine: and aiming at the current event table, constructing an event sequence according to the principle of loading and unloading. The automatic extraction of the loading and unloading events of the oil tanker is realized, the monitoring precision is improved, and the crude oil transportation route is accurately tracked.

Description

Extraction method for loading and unloading events of oil tanker

Technical Field

The invention belongs to the technical field of marine transportation monitoring, and particularly relates to a method for extracting loading and unloading events of an offshore tanker.

Background

Offshore tanker loading and unloading is one of the vital links in the global oil trade, which means that the tanker performs crude oil loading and unloading activities in ports or wharfs and other areas. These activities involve various types of cargo, such as crude oil, refinery products, etc., and are key components of international petroleum trade and logistics transportation. In order to observe the whole transportation route of crude oil, the loading and unloading place and source country of crude oil are tracked, related personnel record loading and unloading events of a tanker, and detailed information and transportation source track related to the loading and unloading process of crude oil are obtained, so that the country of crude oil is defined. This is of great importance for making important strategic decisions.

Currently, the identification of tanker loading and unloading events is typically obtained by personnel in the relevant sector observing the sailing trajectory data of the tanker. The method uses a special ship track monitoring website or tool to conduct manual observation processing, and judges according to the characteristics of loading and unloading events so as to analyze and extract the loading and unloading events of the tanker. However, the loading and unloading activities of the oil tanker are huge and complex, and only are observed manually, so that the oil tanker is not only tedious and inefficient, but also has the problems of subjectivity and misjudgment. For example, during recording, it is not easy to distinguish between anchoring and berthing activities. While the tanker may be loaded and unloaded in the pontoon area outside the port, rather than in the port. In addition, draft changes due to other factors (such as fuel and water consumption, change in the motion state of the crude oil carrier, change in sea water density, and change in tide and water level) may be misjudged as loading and unloading events, etc., resulting in reduced accuracy and reliability of event recording. Therefore, there is a need for an algorithm that automatically identifies loading and unloading events from tanker trace data to improve monitoring accuracy and efficiency.

Disclosure of Invention

The invention aims to provide a high-efficiency and accurate extraction method for a cargo loading and unloading event of a tanker, which solves the problems of low manual extraction efficiency, more subjective misjudgment, insufficient accuracy and reliability and the like in the traditional event extraction method. At the same time, a loading and unloading event sequence can be constructed to track the transportation route and source of crude oil.

In order to solve the technical problems, the technical scheme adopted by the invention is that the extraction method of the cargo loading and unloading events of the tanker comprises the following steps:

step S1: extracting the moving track of a certain oil tanker within a certain period of time;

step S2: extracting a berthing track section using a sliding window;

step S3: processing the mutation at the end of the parking track segment;

step S4: splitting an event with a plurality of draft change points;

step S5: repeating the steps S2, S3 and S4, and storing all parking track segments into a dictionary;

step S6: calculating the draft loading and unloading amount per meter according to the maximum and minimum draft values;

step S7: traversing all berthing track sections, and screening events according to the size of draft change;

step S8: calculating all event related attribute values and storing the event related attribute values into an event table;

step S9: and aiming at the current event table, constructing an event sequence according to the principle of loading and unloading.

Further, the step S1 includes: from complete track data [ P ₁ ，P ₂ ，…，P _n ]Extracting a certain oil ship V for a period of time [ t ] _s ，t _e ]All track data [ P ] within _s ，P _s+1 ，P _s+2 ，…，P _e ]。

Further, the step S2 includes:

step S2.1: traversing Trace Point data [ P ] _s ，P _s+1 ，P _s+2 ，…，P _e ]From the first locus point P _s Starting, W track points are taken each time to form a window W _current ：[P _cur1 ，P _cur2 ，…，P _curW ]；

Step S2.2: calculating the average speed S of the current window track point _avg ，

Wherein if S _avg Less than the speed threshold value theta _sog Adding all track points in the current window into the current parking track segment T _current In (a) and (b);

if S _avg Greater than or equal to the speed threshold value theta _sog Judging whether the speed of each track point is smaller than theta _sog The speed within the window is greater than or equal to theta _sog Track points preceding the track points of (a) are added to the parking track segment T _current In the process, stopping judgment, stopping the process to the current parking track section T _current New track points are added.

Further, the step S3 includes:

taking T _current The last trace point P in (3) _TrackEnd In the complete track data, judging P _TrackEnd With the next track point P _TrackEnd+1 Whether mutation conditions are satisfied; the mutation conditions were:

P _TrackEnd .sog≤θ _sog

and P is _TrackEnd+1 .sog>θ _sog

And P is _TrackEnd .draught≠P _TrackEnd+1 .draught

Wherein sog is the track point speed and draugh is the track point draft;

wherein if the mutation condition is satisfied, P is _TrackEnd The next 20 track points are added into the current parking track section T _current In, i.e. new mooring trajectory segment T _currentNew ：[P _TrackStart ，P _TrackStart+1 ，P _TrackStart+2 ，…，P _TrackEnd ，P _TrackEnd+1 ，…，P _TrackEnd+20 ]；

If not, the processing is not performed.

Further, the step S4 includes:

s4.1: record mooring trajectory segment T _currentNew Calculate T one by one _currentNew The draft change of every two adjacent points in (a) is greater than the draft threshold value theta _draught Track point number N;

s4.2: if N is more than or equal to 2, the track section T will be parked _currentNew Cutting into multiple parking track segments T _current’ 、T _current’+1 、…、T _current’+N The method comprises the steps of carrying out a first treatment on the surface of the The segmentation method comprises the following steps: find two draft change points [ P ] _{DraughtChange1} ，P _{DraughtChange2} ]Intermediate point P of (2) _middle The method for calculating the intermediate point sequence number middle comprises the following steps:

wherein [ P ] _{DraughtChange1} ，P _middle ]For an event fragment, [ P ] _middle+1 ，P _{DraughtChange2} ]Is another event fragment;

if N is less than or equal to 2, no processing is performed.

Further, the step S5 includes:

s5.1: repeating the steps S2, S3 and S4 until all track point data are processed;

s5.2: all extracted berthing track segments [ T ] ₁ ，T ₂ ，…，T _n ]Numbering according to time, taking the number as a key, taking the corresponding parking track segment as a value, and storing the value into a dictionary Dict.

Further, the step S6 includes:

s6.1: screening out all track points with all draft records larger than 10 meters;

s6.2: calculating a minimum draft recorded value D _MinDraught And maximum draft recorded value D _MaxDraught The specific formula is as follows:

further, the step S7 includes:

s7.1: calculating the start-stop draft value D of each track segment _start And D _end ；

S7.2: traversing all parking track segments [ T ] in parking track segment dictionary Dict ₁ ，T ₂ ，…，T _n ]Track segment [ T ] that will satisfy the condition _load1 ，T _load2 ，…，T _loadn ]Screening: the specific screening conditions are as follows:

|D _end -D _start |≥θ _draught 。

further, the step S8 includes:

s8.1: determining each loading and unloading event track segment [ T ] _load1 ，T _load2 ，…，T _loadn ]Whether the loading event or the unloading event is carried out, and the judging conditions are as follows:

if D _start ≤D _end The current event is a shipment event;

if D _start ＞D _end The current event is a discharge event;

s8.2: according to the draft loading and unloading quantity Q per meter _rate Calculating the current incident loading or unloading quantity Q _current The specific calculation formula is as follows:

Q _current ＝Q _rate *|D _end -D _start |

s8.3: the method comprises the specific steps of:

s8.3.1: traversing a track segment T _load Traversing all port polygon data for the current point P (x, y);

s8.3.2: let the current traversed port be H, let each vertex of the polygon where the port boundary is located (x _i ,y _i ) Sequentially arranged to form a port polygon V _harbor ＝{(x ₁ ，y ₁ )，(x ₂ ，y ₂ )，…，(x _n ，y _n ) Emitting a ray from point P (x, y) in the horizontal direction;

s8.3.3: each side E of the polygon is examined,

s8.3.3.1: if the ray intersects the edge E, checking whether the x coordinate of the intersection point is within the horizontal range of the edge E, specifically:

if the x-coordinate of the intersection point is within the horizontal range of the edge E, this intersection point is recorded,

if the x coordinate of the intersection point is not in the horizontal range of the edge E, continuously judging whether the next edge has an intersection point with the ray;

s8.3.3.2: if the ray does not intersect with the edge E, the ray does not intersect with the polygon, and the number of the intersecting points is 0;

s8.3.4: counting the number of all intersection points, and judging whether P is in polygon V according to parity rule _harbor The inner part is specifically as follows:

if the number of intersection points is odd, P is in polygon V _harbor Inner or V _harbor Is considered to be P in port H, and the current event track section T is determined _load Matching with port H, and jumping out for circulation;

if the number of intersection points is even, P is in polygon V _harbor Otherwise, P is not considered to be in port H, and circulation is continued;

s8.4: calculating the residual required field values of all the events, constructing event objects, and finally constructing an event table E _load ：[E ₁ ，E ₂ ，…，E _n ]。

Further, the step S9 includes:

s9.1: traversing event table E _load All events in the middle [ E ] ₁ ，E ₂ ，…，E _n ]；

Wherein, if the current event E _current For loading event and last event E _current-1 For unloading events, then consider to start E from the current event _current For a new sequence of events, all events before belong to a sequence of events E _seqN ；

Otherwise, go on traversing.

Compared with the existing method, the method has a plurality of advantages and positive effects. Firstly, by introducing an algorithm, the method can automatically extract the loading and unloading events of the tanker from the track data of the tanker, and record the detailed information of the related loading and unloading activities. Compared with the traditional manual observation method, the method has the advantage that the monitoring precision is greatly improved. The automatic feature extraction not only saves a great deal of human resources, but also greatly weakens the influence of the problems of artificial subjective judgment and misjudgment, thereby ensuring the accuracy of the identification of loading and unloading events.

Furthermore, by constructing a loading and unloading event sequence, the method makes it more efficient to track the transport route of crude oil. The user can obtain an overall view of the loading and unloading event to more fully understand the flow path of the crude oil and the source of the cargo. In general, compared with the existing method, the method has obvious advantages in the aspects of monitoring precision, recording reliability, crude oil transportation route tracking and the like, and brings substantial technical progress to the field of offshore tanker loading and unloading.

Drawings

FIG. 1 is a flow chart of a method for extracting cargo loading and unloading events of a tanker according to an embodiment of the present invention;

fig. 2 is a schematic diagram of the extraction of a berthing trajectory segment using a sliding window algorithm.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings in which embodiments of the invention are shown. The invention provides a method for extracting a loading and unloading event of a tanker, wherein FIG. 1 shows a specific flow of an algorithm, and FIG. 2 shows a schematic process for extracting a berthing track section by using a sliding window. The method for extracting the loading and unloading events of the tanker can extract the loading and unloading event information from the track data of the tanker, and comprises the following specific implementation steps:

step 1: extracting the moving track of a certain oil tanker in a certain period of time

From complete track data [ P ₁ ，P ₂ ，…，P _n ]Extracting a certain oil ship V for a period of time [ t ] _s ，t _e ]All track data [ P ] within _s ，P _s+1 ，P _s+2 ，…，P _e ]；

Step 2: extraction of berthing trajectory segments using sliding windows

The sliding window algorithm is used for obtaining the track data [ P ] in the step 1 _s ，P _s+1 ，P _s+2 ，…，P _e ]And (5) processing. According to the speed threshold value theta _sog Judging track points in the window under the condition, and extracting a current parking track section T _current ：[P _TrackStart ，P _TrackStart+1 ，P _TrackStart+2 ，…，P _TrackEnd ]. The specific method is as follows:

the sliding window size W is first determined. Traversing Trace Point data [ P ] _s ，P _s+1 ，P _s+2 ，…，P _e ]From the first locus point P _s Starting, W track points are taken each time to form a window W _current ：[P _cur1 ，P _cur2 ，…，P _curW ]. Calculating the average speed S of the current window track point _avg . If S _avg Less than the speed threshold value theta _sog Adding all track points in the current window into the current parking track segment T _current In (a) and (b); otherwise, judging whether the speed of each track point is smaller than theta _sog If the speed of the ith track point is greater than or equal to theta _sog The first i-1 speeds are less than theta _sog The track points joining the berthing track segments T _current And stopping the judgment.

Step 3: abrupt handling of end of berthing trajectory segment

When the average speed of all track points in the window is greater than or equal to the speed threshold value theta _sog When stopping to the current berthing track section T _current New track points are added. Taking T _current The last trace point P in (3) _TrackEnd In the complete track data, judging P _TrackEnd With the next track point P _TrackEnd+1 Whether mutation conditions are satisfied. If so, P is _TrackEnd The next 20 track points are added into the current parking track section T _current In, i.e. new mooring trajectory segment T _currentNew ：[P _TrackStart ，P _TrackStart+1 ，P _TrackStart+2 ，…，P _TrackEnd ，P _TrackEnd+1 ，…，P _TrackEnd+20 ]The method comprises the steps of carrying out a first treatment on the surface of the If not, the processing is not performed. Wherein, the mutation conditions are as follows:

and is also provided with

And P is _TrackEnd .draught≠P _TrackEnd+1 .draught

Where sog is the track point velocity and draugh is the track point draft.

Step 4: splitting events with multiple draft change points

Recording the berthing track segment T processed from step 3 _currentNew Calculate T one by one _currentNew The draft change of every two adjacent points in (a) is greater than the draft threshold value theta _draught Is defined, the number of trace points N. If N is more than or equal to 2, the track section T will be parked _currentNew Cutting into multiple parking track segments T _current’ 、T _current’+1 、…、T _current’+N The method comprises the steps of carrying out a first treatment on the surface of the Otherwise, the processing is not performed.

The segmentation method comprises the following steps: find two draft change points [ P ] _{DraughtChange1} ，P _{DraughtChange2} ]Intermediate point P of (2) _middle The method for calculating the intermediate point sequence number middle comprises the following steps:

then [ P ] _{DraughtChange1} ，P _middle ]For an event fragment, [ P ] _middle+1 ，P _{DraughtChange2} ]Is another event fragment.

Step 5: repeating the steps 2, 3 and 4, and saving all berthing track segments into a dictionary

Repeating the steps 2, 3 and 4,until all the trace point data are processed. All extracted berthing track segments [ T ] ₁ ，T ₂ ，…，T _n ]Numbering according to time, taking the number as a key, taking a corresponding parking track section as a value, and storing the value into a dictionary Dict;

step 6: calculating the draft loading and unloading amount per meter according to the maximum and minimum draft values

From the current minimum draft recorded value D of the vessel _MinDraught And maximum draft recorded value D _MaxDraught Calculating the draft loading and unloading quantity Q of each meter of the current oil tanker V _rate ；

The calculation process is as follows: firstly, screening all track points with draft records larger than 10 meters (normally, draft records are about 10 meters to indicate no load of the tanker), and then calculating the minimum draft record value D _MinDraught And maximum draft recorded value D _MaxDraught And calculate Q according to the following formula _rate ：

Step 7: traversing all berthing track segments, and screening events according to the size of draft change

Traversing all parking track segments [ T ] in the parking track segment dictionary Dict obtained in step 5 ₁ ，T ₂ ，…，T _n ]According to draft change threshold value theta _draught Screening out the track section [ T ] of the loading and unloading events _load1 ，T _load2 ，…，T _loadn ]；

The screening process comprises the following steps: calculating the start-stop draft value D of each track segment _start And D _end And (3) screening out track segments meeting the following conditions:

|D _end -D _start |≥θ _draught

step 8: calculating all event related attribute values and storing the event related attribute values into an event table

All the loading and unloading event track sections [ T ] obtained in the step 7 _load1 ，T _load2 ，…，T _loadn ]Starting to eat according to each event track segmentWater recording D _start And end draft record D _end Judging whether it is loading or unloading event, if D _start ≤D _end The current event is a shipment event; otherwise, the unloading event is performed.

And then according to the draft loading and unloading quantity Q of each meter obtained in the step 6 _rate Calculating the current incident loading or unloading quantity Q _current The calculation formula is as follows:

Q _current ＝Q _rate *|D _end -D _start |

then, judging which port the current track section is positioned in by using a ray method, and carrying out port matching and country matching on the current track section; finally, calculating the field values required by the rest of all the events, constructing event objects, and finally constructing an event table E _load ：[E ₁ ，E ₂ ，…，E _n ]；

The current track segment is determined in which port by using a ray method, and the process is roughly as follows: traversing a track segment T _load Is included. For the current point P (x, y), all port polygon data is traversed. Let the current traversed port be H and its range polygon be V _harbor ＝{(x ₁ ，y ₁ )，(x ₂ ，y ₂ )，…，(x _n ，y _n ) }. A ray is emitted in the horizontal direction from point P (x, y). Each side E of the polygon is checked, and if the ray intersects the side E, it is checked whether the x-coordinate of the intersection point is within the horizontal range of the side E. If yes, recording the intersection point, otherwise, continuing to judge whether the next edge has the intersection point with the ray. Counting the number of all intersection points, and judging whether P is in polygon V according to parity rule _harbor And (3) inner part. If the number of intersection points is odd, P is in polygon V _harbor Inner or V _harbor Is considered to be P in port H, and the current event track section T is determined _load Matching with port H, and jumping out for circulation; if the number of intersection points is even, P is in polygon V _harbor In addition, P is not considered to be in port H and continues to circulate.

Step 9: for the current event table, an event sequence is constructed according to the principle of loading and unloading

Traversing the event table E resulting from step 8 _load Constructing an event sequence E according to the principle of' loading before unloading _seq ：[E _seq1-1 ，E _seq1 -2，…，E _seqN-M ]. The event sequence is constructed according to the principle of 'loading before unloading'. I.e. traverse event table E _load All events in the middle [ E ] ₁ ，E ₂ ，…，E _n ]If the current event E _current For loading event and last event E _current-1 For unloading events, then consider to start E from the current event _current For a new sequence of events, all events before belong to a sequence of events E _seqN The method comprises the steps of carrying out a first treatment on the surface of the Otherwise, continuing traversing.

The method for extracting the loading and unloading events of the offshore tanker has remarkable technical advantages and innovation points in the field of offshore transportation monitoring, and realizes efficient, accurate and automatic extraction of the loading and unloading events. Compared with the traditional manual observation method, the method has the following optimal effects:

automation and efficiency: the automatic extraction of the loading and unloading events of the tanker is realized by introducing an algorithm, and the tedious and low-efficiency manual observation process in the traditional method can be replaced. The application of the algorithm greatly improves the monitoring precision, saves a great amount of human resources, and ensures that the event extraction is more efficient;

weakening subjectivity and misjudgment problems: by means of automatic feature extraction of loading and unloading events, the method reduces the influence of artificial subjective judgment and misjudgment problems. For huge and complex cargo loading and unloading activities of the tanker, the objectivity of the algorithm is helpful for ensuring the accuracy of event recording;

calculation of maximum and minimum draft: and (3) integrating expert experience and data calculation, considering the maximum and minimum draft records of the tanker during transportation, and calculating the draft loading and unloading amount per meter according to the maximum and minimum draft records. The method combines actual transportation data, and ensures that the calculation of the loading and unloading amount of each oil tanker per meter is more accurate;

loading and unloading event sequence construction: the method can construct a loading and unloading event sequence to help track the transportation route and source of crude oil. The user can comprehensively know the flow path of the crude oil and the cargo source, and more comprehensive information is provided for decision making.

Therefore, the invention has the advantages of improving the monitoring efficiency of loading and unloading events, recording the credibility, tracking the crude oil transportation route and the like, and brings substantial technical progress to the field of offshore tanker loading and unloading.

Claims (10)

1. A method of retrieving a tanker loading and unloading event, comprising the steps of:

step S1: extracting the moving track of a certain oil tanker within a certain period of time;

step S2: extracting a berthing track section using a sliding window;

step S3: processing the mutation at the end of the parking track segment;

step S4: splitting an event with a plurality of draft change points;

step S5: repeating the steps S2, S3 and S4, and storing all parking track segments into a dictionary;

step S6: calculating the draft loading and unloading amount per meter according to the maximum and minimum draft values;

step S7: traversing all berthing track sections, and screening events according to the size of draft change;

step S8: calculating all event related attribute values and storing the event related attribute values into an event table;

step S9: and aiming at the current event table, constructing an event sequence according to the principle of loading and unloading.

2. The method of extracting a tanker loading event according to claim 1, wherein said step S1 comprises: from complete track data [ P ₁ ，P ₂ ，…，P _n ]Extracting a certain oil ship V for a period of time [ t ] _s ，t _e ]All track data [ P ] within _s ，P _s+1 ，P _s+2 ，…，P _e ]。

3. The method of extracting a tanker loading event according to claim 1, wherein said step S2 comprises:

step S2.1: traversing Trace Point data [ P ] _s ，P _s+1 ，P _s+2 ，…，P _e ]From the first locus point P _s Starting, W track points are taken each time to form a window W _current ：[P _cur1 ，P _cur2 ，…，P _curW ]；

Step S2.2: calculating the average speed S of the current window track point _avg ，

Wherein if S _avg Less than the speed threshold value theta _sog Adding all track points in the current window into the current parking track segment T _current In (a) and (b);

if S _avg Greater than or equal to the speed threshold value theta _sog Judging whether the speed of each track point is smaller than theta _sog The speed within the window is greater than or equal to theta _sog Track points preceding the track points of (a) are added to the parking track segment T _current In the process, stopping judgment, stopping the process to the current parking track section T _current New track points are added.

4. A method of extracting a tanker loading event according to claim 3, wherein said step S3 comprises:

taking T _current The last trace point P in (3) _TrackEnd In the complete track data, judging P _TrackEnd With the next track point P _TrackEnd+1 Whether mutation conditions are satisfied; the mutation conditions were:

P _TrackEnd .sog≤θ _sog

and P is _TrackEnd+1 .sog>θ _sog

And P is _TrackEnd .draught≠PT _rackEnd+1 .draught

Wherein sog is the track point speed and draugh is the track point draft;

wherein if the mutation condition is satisfied, P is _TrackEnd The next 20 track points are added into the current parking track section T _current In, i.e. new mooring trajectory segment T _currentNew ：[P _TrackStart ，P _TrackStart+1 ，P _TrackStart+2 ，…，P _TrackEnd ，P _TrackEnd+1 ，…，P _TrackEnd+20 ]；

If not, the processing is not performed.

5. The method of claim 4, wherein said step S4 comprises:

s4.1: record mooring trajectory segment T _currentNew Calculate T one by one _currentNew The draft change of every two adjacent points in (a) is greater than the draft threshold value theta _draught Track point number N;

s4.2: if N is more than or equal to 2, the track section T will be parked _currentNew Cutting into multiple parking track segments T _current’ 、T _current’+1 、…、T _current’+N The method comprises the steps of carrying out a first treatment on the surface of the The segmentation method comprises the following steps: find two draft change points [ P ] _{DraughtChange1} ，P _{DraughtChange2} ]Intermediate point P of (2) _middle The method for calculating the intermediate point sequence number middle comprises the following steps:

wherein [ P ] _{DraughtChange1} ，P _middle ]For an event fragment, [ P ] _middle+1 ，P _{DraughtChange2} ]Is another event fragment;

if N is less than or equal to 2, no processing is performed.

6. A method of extracting a tanker loading event according to claim 1 or 5, wherein said step S5 comprises:

s5.1: repeating the steps S2, S3 and S4 until all track point data are processed;

s5.2: all extracted berthing track segments [ T ] ₁ ，T ₂ ，…，T _n ]Numbering is carried out according to the time of the process,and taking the serial number as a key, taking the corresponding parking track segment as a value, and storing the value into a dictionary Dict.

7. The method of claim 6, wherein said step S6 comprises:

s6.1: screening out all track points with all draft records larger than 10 meters;

s6.2: calculating a minimum draft recorded value D _MinDraught And maximum draft recorded value D _MaxDraught The specific formula is as follows:

8. the method of claim 6, wherein step S7 includes:

s7.1: calculating the start-stop draft value D of each track segment _start And D _end ；

S7.2: traversing all parking track segments [ T ] in parking track segment dictionary Dict ₁ ，T ₂ ，…，T _n ]Track segment [ T ] that will satisfy the condition _load1 ，T _load2 ，…，T _loadn ]Screening: the specific screening conditions are as follows:

|D _end -D _start |≥θ _draught 。

9. the method of claim 8, wherein said step S8 comprises:

s8.1: determining each loading and unloading event track segment [ T ] _load1 ，T _load2 ，…，T _loadn ]Whether the loading event or the unloading event is carried out, and the judging conditions are as follows:

if D _start ≤D _end The current event is a shipment event;

if D _start ＞D _end The current event is a discharge event;

s8.2: according to the draft loading and unloading quantity Q per meter _rate Calculating the current incident loading or unloading quantity Q _current The specific calculation formula is as follows:

Q _current ＝Q _rate *|D _end -D _start |

s8.3: the method comprises the specific steps of:

s8.3.1: traversing a track segment T _load Traversing all port polygon data for the current point P (x, y);

s8.3.2: let the current traversed port be H, let each vertex of the polygon where the port boundary is located (x _i ,y _i ) Sequentially arranged to form a port polygon V _harbor ＝{(x ₁ ，y ₁ )，(x ₂ ，y ₂ )，…，(x _n ，y _n ) Emitting a ray from point P (x, y) in the horizontal direction;

s8.3.3: each side E of the polygon is examined,

s8.3.3.1: if the ray intersects the edge E, checking whether the x coordinate of the intersection point is within the horizontal range of the edge E, specifically:

if the x-coordinate of the intersection point is within the horizontal range of the edge E, this intersection point is recorded,

if the x coordinate of the intersection point is not in the horizontal range of the edge E, continuously judging whether the next edge has an intersection point with the ray;

s8.3.3.2: if the ray does not intersect with the edge E, the ray does not intersect with the polygon, and the number of the intersecting points is 0;

s8.3.4: counting the number of all intersection points, and judging whether P is in polygon V according to parity rule _harbor The inner part is specifically as follows:

if the number of intersection points is odd, P is in polygon V _harbor Inner or V _harbor Is considered to be P in port H, and the current event track section T is determined _load Matching with port H, and jumping out for circulation;

if the number of intersection points is even, P is in polygon V _harbor Otherwise, P is not considered to be in port H, and circulation is continued;

s8.4: calculating the residual required field values of all the events, constructing event objects, and finally constructing an event table E _load ：[E ₁ ，E ₂ ，…，E _n ]。

10. The method of claim 9, wherein said step S9 comprises:

s9.1: traversing event table E _load All events in the middle [ E ] ₁ ，E ₂ ，…，E _n ]；

Wherein, if the current event E _current For loading event and last event E _current-1 For unloading events, then consider to start E from the current event _current For a new sequence of events, all events before belong to a sequence of events E _seqN ；

Otherwise, go on traversing.